,a ,,guide ,,= ,,! ,,dissection         
,,( ,,! ,,dogfi%                        
7,,squalus ,,acan?ias7                  
,by                            ,,lawr5ce
 ,e4 ,,griff9                           
,pr(essor ( ,biology 9 ,re$ ,college    
,,?ird ,,edition                        
,portl&1 ,oregon                        
#aibb                                   
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,copyright1 #aibb                       
by                           ,,lawr5ce  
,e4 ,,griff9                            
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,a ,guide = ! ,dissection               
( ! ,dogfi%  ,! small %>ks :i* ab\nd    
along ! coa/s ( ! ,unit$ ,/ates are     
commonly call$ 8dogfi%0 by fi%]m5 &     
o!rs4 ,! 8dogfi%0 ( inl& wat]s belongs  
to an entirely diff]5t gr\p4 ,two       
species ( %>ks are caught 9 numb]s & us$
 9 laboratory "w1 ! 8sp9y dogfi%0       
7,squalus acan?ias7 & ! 8smoo? dogfi%0  

7,eugaleus galeus74 ,! fir/ is easily   
di/+ui%$ by ! %>p sp9e 9 front ( ea*    
dorsal f94 ,squalus acan?ias is (t5     
ref]r$ to "u ! synonym ,acan?ias        
vulg>is1 :ile ,eugaleus galeus is m     
frequ5tly nam$ ei!r ,mu/elus canis or   
,galeus canis4 ,! hi/ories ( ^! names & 
sy/ematic descriptions ( ! species are  
conta9$ 9 ,samuel ,g>man's ,monograph on
 ! ,elasmobran*s4  ,sev]al sizes (      
dogfi% are furni%$ by deal]s4 ,we       
consid] x be/ to pur*ase l>ge1 fully    
develop$ specim5s4 ,! small specim5s may
 be a little m conv5i5t to h&le1 b !    
l>ge ones h ! important advantage ( be+ 
sexually mature1 :ile blood vessels &   
n]ves are dissect$ bett] 9 l>ge ?an 9   
small specim5s4 ,also1 a numb] (        
/ructures are v diff]5t 9 mature animals
 f _! condition 9 "y ones4 ,deal]s %\ld 
be reque/$ to furni% fi% ) f9s & tails  
complete in/ead ( trimm$4 ,x is an      
advantage to issue to ! class equal     
numb]s ( bo? sexes4  ,an entire specim5 
& an extra head may be requir$ by ea*   

/ud5t = a ?or\gh dissection4 ,x w\ld be 
bett] if ! head 7 cut (f j beh9d !      
pectoral f9s1 in/ead ( 9 front ( !m z is
 usually done1 s t ! vagus &            
hypobran*ial n]ves may be dissect$ m    
completely4  ,! sp9y dogfi%1 :i* is !   
p>ticul> subject ( ?is guide1 is !      
species mo/ frequ5tly suppli$ to        
laboratories4 ,h[ev]1 ! sp9y & smoo?    
dogfi%es are s mu* alike t ! latt] may  
be easily dissect$ ) ^! directions4 ,:]e
 m>k$ diff]5ces betwe5 ! =ms exi/ !     
/ructure ( ,eugaleus is describ$        
sep>ately4  ,! /ud5t ( anatomy %\ld     
realize t dissection is = ! purpose (   
enabl+ him to see = himself ! /ructures 
:i* exi/1 & t no dissection is          
satisfactory until ! anatomical         
arrangem5ts m5tion$ 9 ! text c be       
completely demon/rat$ 9 8 specim54  ,!  
importance ( kn[+ ! /ructure ( !        
elasmobran* is s great 9 comp>ative     
anatomy & embryology t x is wor? :ile to
 make a ?or\gh dissection ( "o ( ?is    
class4 ,z ! dogfi% is frequ5tly ! fir/  

major v]tebrate =m to be /udi$ 9 detail1
 ^! directions h be5 writt5 to con=m to 
! ne$s ( ! /ud5t :o is beg9n+ comp>ative
 anatomy4 ,! arrangem5t ( sections 9 ?is
 guide is int5d$ to p]mit ! omission (  
"s :i* x may n be consid]$ desirable to 
include 9 ! "w ( a class4               
,,ext]nal ,,*>act]s  ,! sp9dle-%ap$ body
 tap]s f ne> ! middle t[>d bo? head &   
tail2 ! head is flatt5$ on bo? ! dorsal 
& v5tral sides1 :ile ! rema9d] ( ! body 
is ne>ly r\nd1 ) a lat]al compression   
:i* is n pron\nc$ except 9 ! caudal     
portion4  ,! g5]al color ( ! back &     
sides is gray2 d>ke/ above1 :]e ! sk9 is
 spott$ ) scatt]$1 small1 r\nd1 light   
spots4 ,! color ( ! upp] p>ts %ades into
 ! yell[ :ite ( ! v5tral surface4  ,c   
head1 trunk1 & tail regions be di/+ui%$8
 ,if s1 :at *>act]s det]m9e ! ext5t (   
ea*8  ,a little above ! middle ( ! side 
( ! body is ! lat]al l9e1 7di/+ui%$     
p>tly by color1 p>tly by be+ slightly   
elevat$71 :i* ext5ds f ! back ( ! head  
to ! tail4 ,cut ?r\gh ! sk9 across !    

lat]al l9e at sev]al po9ts along ! body 
& notice ! canal :i* lies 9 ! d]mis "u !
 lat]al l9e4 ,?is is ! lat]al l9e canal1
 :i* op5s to ! surface by num]\s pores  
7too m9ute to be se571 & conta9s a s]ies
 ( special s5se organs along its dorsal 
& inn] surfaces4 ,ne> ! base ( ! caudal 
f9 ! lat]al l9e canal passes into a     
groove :i* cont9ues ! lat]al l9e to )9 a
 %ort di/ance ( ! edge ( ! f94 ,! lat]al
 l9e canal 9 its developm5t beg9s z a   
groove along ! side ( ! body :i* becomes
 clos$ by ! fusion ( its edge except 9  
?is t]m9al portion4  ,! op5 groove does 
n appe> 9 ,eugaleus4  ,9 ! midl9e ( !   
body are two triangul> dorsal f9s1 ea*  
atta*$ to ! body = ab\t half its l5g?4  
,! basal portion ( ea* is ?ick &        
muscul>1 & conta9s support+ c>tilages   
emb$d$ 9 ! muscles4 ,! rema9d] ( ! f9 is
 flexible & semi-transp>5t1 horny       
f9-rays be+ fa9tly visible betwe5 !     
lay]s ( sk94 ,9 front ( ea* f9 is a     
/rong sp9e :i* seems to s]ve bo? z a    
cutwat] & a weapon ( def5se4 7,eugaleus 

has no sp9es47  ,! broad1 pair$1        
pectoral f9s1 hav+ ! g5]al *>act]i/ics (
 ! dorsals1 spr+ f ! v5tral edges ( !   
body j back ( ! head4 ,a h>d b> (       
c>tilage connect+ ! bases ( ! pectoral  
f9s c be felt ?r\gh ! sk9 ( ! v5tral    
surface ( ! body4 ,?is is ! v5tral "p ( 
! pectoral girdle4  ,f>!r back1 & also  
on ! v5tral surface1 are ! pair$ pelvic 
f9s4 ,! pelvic girdle c be felt ?r\gh ! 
sk9 betwe5 ! bases ( ^! f9s4 ,if !      
specim5 is a male1 x w h a f+]like      
process project+ backw>d f ! base &     
along ! inn] side ( ea* pelvic f94 ,^!  
organs1 :i* atta9 a consid]able size 9  
adults1 are modifi$ portions ( ! pelvic 
f9 us$ z copulatory organs4 ,!y are nam$
 v>i\sly clasp]s1 myxopt]ygia1 or       
pt]ygopodia4 ,a groove runs along !     
dorsal side ( ! clasp] f ! tip to ne> ! 
base1 :]e x op5s into a long sac 7gl&ula
 pt]ygopodia7 ext5d+ "s di/ance 9 front 
( ! pelvic f9s j )9 ! sk9 ( ! v5tral    
surface4 ,by feel+ a c>tilag9\s axis ( !
 clasp] c be discov]$1 :i* ext5ds to !  

tip ( ! organ4 ,on ! dorsal surface &   
ne> ! end ( ! clasp] is a %>p groov$    
sp9e on ! out] side1 & a /rongly recurv$
 hook on ! inn] side1 bo? almo/ hidd5 by
 a flap project+ f ! inn] edge ( !      
groove4 ,?is flap is /iff5$ by a s]ies (
 small c>tilages simil> to ! radial     
c>tilages 9 ! bases ( ! f9s4  ,! caudal 
f9 is asymmetrical1 ext5d+ along !      
dorsal & v5tral edges ( ! po/]ior end ( 
! body4 ,obs]ve ! upw>d b5d ( ! v]tebral
 column :i* occurs 9 ! tail2 x is ?is "*
 :i* m>ks ! het]oc]cal type ( tail4     
,eugaleus has a m$ian v5tral1 or anal1  
f9 a %ort di/ance ant]ior to ! caudal   
f94  ,! m\? is a broad transv]se slit ^u
 ! v5tral surface ( ! head4 ,!          
c>tilag9\s jaws c be se5 & felt j )9 !  
m\?4 ,bo? upp] & l[] jaws are arm$ ) r[s
 ( flat1 %>ply po9t$ tee?4 ,/udy _!     
arrangem5t & approximate numb]4 ,jaws ( 
previ\sly dissect$ specim5s %\ld be     
exam9$ "u a dissection microscope4 ,!   
exact =m & arrangem5t ( ! functional    
tee? c !n be asc]ta9$ easily1 & an      

exam9ation ( ! inn] surface ( ei!r jaw w
 disclose sev]al r[s ( develop+ tee?4 ,z
 ! "y tee? develop !y move1 a r[ at a   
"t1 into position on ! edge ( ! jaw2 !  
olde/ tee?1 occupy+ ! out] r[1 are %$ at
 ab\t ! same "t4  ,! upp] jaw is p>tly  
ov]hung by a lip-l fold ( sk94 ,at ea*  
side ( ! m\? is a pocket1 direct$       
obliquely1 hav+ no communication ) !    
m\?4 ,^! labial pockets provide places =
 ! labial c>tilages 7:i* c be felt along
 ! m$ial edges7 :5 ! m\? is clos$1 &    
also af=d fre$om ( motion to ! m&ible4  
,cut along ! inn] edge ( ! labial pocket
 & expose ! c>tilages = exam9ation4 7,! 
labial pocket ( ,eugaleus is mu* small]1
 & 9 front ( ! corn] ( ! m\? r ?an      
lat]al to x4 ,! two c>tilages are       
completely sep>at$ f ea* o!r1 ! po/]ior 
"o sc>cely rea*+ ! pocket47  ,9 front ( 
! m\? are ! no/rils1 _! ap]tures        
app>5tly divid$ by project+ flaps ( !   
ant]ior m>g94 ,explore ! cavity ( !     
no/ril ) a probe to get a good idea (   
its size & =m4  ,betwe5 ! pelvic f9s is 

! cloaca1 a l>ge depression into :i* op5
 ! alim5t>y canal1 ! excretory & g5ital 
ducts1 & ! abdom9al pores4 ,! op5+ ( !  
alim5t>y canal1 ! anus1 is at ! ant]ior 
end ( ! cloaca4 ,9 pres]v$ specim5s "p (
 ! inte/9e is frequ5tly ev]t$ ?r\gh !   
anus4 ,a l>ge fle%y process1 be>+ a pore
 at its tip1 projects f ! dorsal wall ( 
! cloaca4 ,9 ! male ?is is ! uro-g5ital 
papilla2 9 ! female ! ur9>y papilla4 ,9 
! female a g5ital pore1 ! op5+ ( !      
oviduct1 is f\nd on ei!r side ( !       
papilla4 ,an abdom9al pore1 lead+ into !
 abdom9al cavity1 is f\nd on ea* side ( 
! cloaca at ! po/]ior m>g94 ,^! are     
frequ5tly clos$ 9 "y specim5s4  ,!      
cloaca ( ,eugaleus has a comp>atively   
small op5+ ^u ! v5tral surface1 :i* mu/ 
be enl>g$ be=e ! p>ts describ$ c be se5 
well4  ,! lat]ally plac$ eyes are )\t   
lids2 obs]ve ! consid]able diff]5ce 9 ! 
am\nt ( curvature ( ! dorsal & v5tral   
m>g9s ( ! eye4  ,9 ,eugaleus !re is a   
fold ( sk9 /ret*$ across ! l[] "p ( !   
eye :i* s]ves z an eye-lid1 &           

corresponds to ! s-call$ 8?ird eye-lid0 
or nictitat+ membrane ( o!r v]tebrates4 
,on ea* side ( ! neck are five v]tical  
gill-clefts1 ea* lead+ into a l>ge gill 
p\* :i* communicates ) ! ph>ynx by an   
int]nal op5+4 ,pass a probe ?r\gh a     
gill-cleft into ! m\?4  ,back ( ea* eye 
is a small ap]ture1 ! spiracle2 explore 
?is cavity ) a probe4 ,! spiracle is to 
be consid]$ a gill-cleft mov$ =w>d ^u ! 
head & l>gely1 ?\gh n entirely1 depriv$ 
( its respiratory functions4  ,9 ! c5t] 
( ! dorsal surface ( ! head1 betwe5 !   
spiracles1 are two pores1 ! ext]nal     
op5+s ( ! endolymphatic ducts :i*       
communicate ) ! int]nal e>4 ,l>ge numb]s
 ( small] pores c be f\nd on all        
surfaces ( ! head1 "s 9 gr\ps1 "s       
arrang$ l9e>ly1 _m scatt]$4 ,mo/ ( ^?   
arrang$ 9 l9es lead into ! s5sory canal 
sy/em :i* cont9ues f ! lat]al l9e canal 
^u ! head1 :ile ! majority ( ! o!rs     
belong to a sep>ate type ( s5se organs1 
! ampullae ( ,lor5z9i4  ,make a cut     
encircl+ ! pores ( ! endolymphatic ducts

 & close to !m4 ,d n remove ?is piece ( 
sk94 ,f x make a m$ian incision =w>d to 
! tip ( ! sn\t & back z f> z ! level ( !
 fir/ gill slit4 ,/>t+ at ?is incision  
"w ! sk9 (f f ! tissues b5ea? x4 ,?is   
mu/ be a c>eful1 close dissection4 ,:5 !
 lat]al l9e is rea*$ x w be se5 t !     
lat]al l9e canal is cont9u$ ^u ! head & 
is jo9$ by sev]al o!rs4 ,by look+ ?r\gh 
! loos5$ sk9 t[>d ! light ! pores c be  
se5 :i* lead f ! canals to ! surface4 ,9
 ! holl[ ( ! skull 9 front ( & above !  
eye is a l>ge gr\p ( tubules :i* op5    
?r\gh ! pores s conspicu\s at ?is po9t4 
,at ! int]nal end ( ea* tubule is a     
slight enl>gem5t1 ( d5s] tissue1 ) :i* a
 delicate n]ve /r& c (t5 be se5         
connect$4 ,! n]ve /r&s c be trac$ to a  
l>ge n]ve pass+ above ! eye & di/ribut$ 
to ! sn\t4 ,^! tubules are ! ampullae ( 
,lor5z9i4 ,?is gr\p ( ampullae1 :i* may 
be call$ ! dorsal gr\p1 is q def9itely  
dem>k$4 ,x w be not$ t ! inn] ends ( !  
ampullae are gr\p$ 9 a mu* small] area  
?an _! pores4  ,betwe5 ! spiracle & !   

fir/ gill slit w be f\nd a lat]al gr\p (
 simil> organs4 ,notice ! arrangem5t (  
_! tubules & pores4 ,"u ! sn\t are two  
gr\ps ( ampullae on ea* side ( ! midl9e4
 ,! inn] v5tral gr\p is sep>at$ f ! out]
 v5tral gr\p by ! lat]al b> ( ! ro/ral  
c>tilage4 ,"s ( ! tubules ( ! out]      
v5tral gr\p w be f\nd to ext5d to pores 
situat$ at ! sides ( & beh9d ! m\?4  ,an
 adult fi% possesses f #abjj to #aijj   
ampullae ( ,lor5z9i4 ,_! function is n  
well und]/ood1 b x has be5 sugge/$ t !y 
are organs responsive to /imuli (       
pressure1 ei!r ( curr5ts or wat]1 or    
result+ f dep?1 or ev5 ( deep tones4  ,!
 sy/em ( s5sory canals consi/s ( !      
foll[+ memb]s on ea* side ( ! head3--   
,a supra-orbital1 pass+ above ! eye to !
 end ( ! sn\t & b5d+ back on ! v5tral   
surface to jo9 ! infra-orbital4  ,an    
infra-orbital1 :i* bran*es (f f !       
supra-orbital & passes v5trad betwe5 !  
eye & ! spiracle1 !n turns =w>d along ! 
v5tral m>g9 ( ! orbit1 & f9ally b5ds    
t[>d ! midl9e & ext5ds to ! tip ( !     

sn\t4  ,a hyom&ibul>1 :i* leaves !      
infra-orbital bel[ ! eye & runs back    
beyond ! angle ( ! m\?4  ,a %ort        
m&ibul>1 on ! m&ible close to ! angle ( 
! m\?1 :i* is n connect$ ) ! o!r canals4
  ,! canal sy/ems ( ! "r & left sides   
are connect$ by a supratemporal canal j 
beh9d ! endolymphatic pores1 & (t5 by an
 ana/omosis ( ! infra-orbital canals 9  
front ( ! m\?4  ,on "s specim5s two     
cresc5tic r[s ( pores c be f\nd betwe5 !
 bases ( ! pectoral f9s1 :i* repres5t a 
?ird type ( s5sory organ1 ! pit organs1 
closely relat$ g5etically to ! s5sory   
canals4 ,two long] l9es ( pit organs1 7!
 m&ibul> pit organs71 w be f\nd a %ort  
di/ance beh9d ! m\?4 ,simil> pit organs 
are f\nd 9 front ( ! endolymphatic      
pores1 & above ! ant]ior "p ( ! lat]al  
l9e4  ,except = a few small areas !     
entire surface ( ! body is cov]$ )      
small1 %>p-po9t$ d5ticles 7placoid      
scales74 ,ea* consi/s ( a diamond-%ap$  
basal plate emb$d$ 9 ! d]mis1 f :i*     
projects a leaf-l1 backw>d direct$ sp9e4

 ,a piece ( sk9 %\ld be remov$ & exam9$ 
"u a l[ magnification4 ,! d]mis is s    
d5se & pigm5t$ t ! basal plate is n     
easily /udi$ )\t fur!r manipulation4 ,= 
?is purpose boil a piece ( sk9 9 #e     
cau/ic pota% solution until x is s(t5$1 
b n till x dis9tegrates4 ,!n cle> x 9   
glyc]9e4 ,exam9e ! individual d5ticles  
"u a high] magnification4 ,! d5ticle    
consi/s ( d5t9e1 ! sp9e be+ ( a mu* d5s]
 /ructure ?an ! base4 ,! tee? & ! l>ge  
sp9es ( ! f9s & clasp]s are also compos$
 ( d5t9e & may be consid]$ z modifi$    
placoid scales4 ,d5ticles1 tee?1 & sp9es
 are cov]$ ) a %9y1 enamel-l lay] :i*1  
h[ev]1 does n appe> to be true enamel   
su* z cov]s ! tee? ( high] v]tebrates4  
,! %ape ( ! scales & _! clos5ess v>y on 
diff]5t regions ( ! body1 & !re are     
c]ta9 regions entirely free f !m1       
namely1 back ( ! dorsal1 pectoral &     
pelvic f9s1 ! m$io-dorsal surfaces ( !  
clasp]s1 inside ! upp] lip & ! labial   
pockets4                                
,,dissection ,,( ,,! ,,abdom9al ,,visc]a

  ,place ! dogfi% on its back &1 comm5c+
 at ! middle ( ! abdom51 make an        
incision ?r\gh ! body wall a qu>t] ( an 
in* to "o side ( ! midl9e4 ,c>ry ?is    
=w>d to ! pectoral girdle & backw>d     
?r\gh ! pelvic girdle to ! cloaca2 n1   
h[ev]1 cutt+ ! wall ( ! cloaca4  ,a l>ge
 ve91 ! lat]al ve91 runs along ! inn]   
surface ( ea* lat]al wall ( ! abdom54   
,aft] id5tify+ ^!1 cut ?r\gh ! body wall
 transv]sely on bo? sides ( ! abdom5 at 
! level ( ! po/]ior atta*m5t ( !        
pectoral f9 z f> z ! lat]al ve94 ,turn !
 flaps outw>d & fa/54  ,! coelom or     
body-cavity consi/s ( two portions1 !   
abdom9al & p]ic>dial cavities4 ,!       
abdom9al cavity1 :i* has n[ be5 op5$1   
ext5ds f ! pectoral girdle to ! cloaca &
 along ! sides ( ! latt]2 x communicates
 ) ! ext]ior ?r\gh ! abdom9al pores on  
ei!r side ( ! cloaca4 ,pass a bri/le or 
probe ?r\gh ea* abdom9al pore into !    
cloaca4  ,)\t dissect+1 id5tify ! foll[+
 p>ts & obs]ve _! relations3  ,!        
p]itoneum1 ! smoo? l9+ ( ! body wall1   

:i* is reflect$ ov] ! visc]a4  ,! liv]1 
a l>ge1 gray organ atta*$ ant]iorly &   
almo/ completely divid$ into two lobes  
:i* ext5d well back along ! sides ( !   
abdom9al cavity4  ,! /oma*1 ly+ betwe5 !
 lobes ( ! liv]4 ,its po/]ior end is b5t
 =w>d ^u itself 9 ! =m ( a ,u4 ,! two   
limbs ( ! /oma* are kn[n z ! c>diac     
7proximal7 & pyloric 7di/al71           
respectively4 ,) a second turn to ! "r &
 backw>d x ent]s ! inte/9e4  ,! inte/9e1
 a l>ge1 ?9-wall$ tube ext5d+ f ! /oma* 
to ! cloaca4  ,! sple51 a d>k1 triangul>
 mass atta*$ to ! po/]ior bord] ( !     
curve ( ! /oma*4  ,! sple5 ( ,eugaleus  
is a long1 sl5d] body ext5d+ f ! middle 
( ! proximal limb ( ! /oma* ar\nd !     
po/]ior end ( t organ & =w>d aga9 along 
! di/al limb = two-?irds ( ! l5g? ( !   
latt]4  ,! pancreas1 a firm :ite mass ! 
l>g] "p ( :i* lies dorsal to ! po/]ior  
end ( ! /oma*4 ,"o extremity lies on !  
v5tral surface ( ! junction ( ! /oma* & 
inte/9e4  ,! reproductive gl&s1 7ov>ies 
or te/es71 ly+ on ei!r side ( ! midl9e  

dorsal to ! ant]ior portion ( ! liv]2 !y
 may be mi/ak5 = small lobes ( ! liv]4  
,! reproductive gl&s ( ,eugaleus are    
long bodies ly+ above ! /oma* & inte/9e4
 ,!y are fus$ to ea* o!r = almo/ _!     
entire l5g?4  ,! kidneys1 two long1     
sl5d]1 br[ni% bodies ext5d+ along !     
dorsal wall ( ! abdom9al cavity outside 
! p]itoneum1 on ei!r side ( ! midl9e4   
,! dogfi% usually furni%$ = dissection  
are immature1 hav+ ! g5ital gl&s & ducts
 only p>tly develop$4 ,9 mature females 
! oviducts are conspicu\s tubes v5tral  
to ! kidneys4 ,9 "y specim5s !y appe> z 
sl5d]1 :ite tubes ext5d+ along ! inn]   
bord]s ( ! kidneys4 ,ant]iorly1 !       
oviducts pass v5trad ov] ! front ( !    
liv] to ! v5tral wall ( ! body2 at !    
same "t !y unite to =m a funnel1 ! o/ium
 tubae1 :i* op5s into ! coelom4         
,ve/igial oviducts op5+ into ! coelom   
are f\nd 9 ! same position 9 males4  ,9 
males1 ! vasa def]5tia appe> z sl5d]1   
irregul>ly coil$ :ite tubules ly+ ne> ! 
m$ial bord] ( ! kidneys2 !y are mu* less

 conspicu\s ?an ! oviducts1 especially 9
 "y males4  ,,! ,,alim5t>y ,,sy/em4 ,9  
dissect+ ! foll[+ organs1 c>e %\ld be   
tak5 n to break ! connections ( ! organs
 ) ea* o!r or ) o!r p>ts1 or to cut     
blood vessels4 ,organs %\ld n be remov$ 
until su* proc$ure is direct$4  ,! m\? &
 ph>ynx c be /udi$ to bett] advantage   
lat] ) ! dissection ( portions ( !      
vascul> sy/em4  ,! oesophagus c be se5  
above ! liv]1 by press+ t organ aside1 z
 a some:at con/rict$ tube ent]+ !       
ant]ior end ( ! abdom9al cavity4 ,x     
imm$iately jo9s ! /oma*1 :i* is m or    
less exp&$ accord+ to ! am\nt ( food    
conta9$ 9 x4  ,! /oma* passes directly  
back = m ?an half ( ! l5g? ( ! abdom9al 
cavity1 !n turns abruptly =w>d1 =m+ a   
di/al limb ab\t a ?ird z long z !       
proximal4 7,two-?irds to ?ree-qu>t]s z  
long 9 ,eugaleus47 ,! di/al limb ends ) 
a %>p turn to ! "r1 :]e x is con/rict$  
by ! pyloric sph9ct]1 :i* m>ks ! end ( !
 /oma*4  ,! n>r[ beg9n+ ( ! inte/9e =m+ 
! turn to ! "r & backw>d is frequ5tly   

di/+ui%$ z ! duod5um4 ,x leads f ! /oma*
 directly into ! l>ge inte/9e1 a wide1  
/raight tube m>k$ ext]nally by a spiral 
l9e ( sev]al turns4 ,! l>ge inte/9e     
n>r[s po/]iorly1 =m+ a region some:at   
arbitr>ily t]m$ ! rectum1 :i* op5s into 
! cloaca ?r\gh ! anus4  ,dorsal to !    
rectum & atta*$ to t body is a n>r[     
sp9dle-%ap$ body1 ! rectal or digiti=m  
gl&4  ,! liv] is atta*$ to ! ant]ior    
wall by a broad base1 ! p]itoneum be+   
reflect$ ov] ! entire rema9+ surface4 ,!
 atta*+ fold ( ! p]itoneum is frequ5tly 
call$ ! susp5sory ligam5t4 ,! p]itoneum1
 or coelomic epi!lium1 c be dissect$    
easily f ! surface ( ! liv] or ! kidney 
& its extreme ?9ness & delicacy not$4 ,x
 consi/s ( a s+le lay] ( cells4  ,mo/ ( 
! abdom9al organs are susp5d$ f ! dorsal
 wall ( ! body cavity by delicate       
membrane\s %eets1 or mes5t]ies4 ,simil> 
%eets betwe5 ! organs are ! om5ta4 ,!   
/oma* is susp5d$ by a mesoga/]1 :i*     
ext5ds z a free fold along ! body z f> z
 ! ant]ior mes5t]ic & li5oga/ric        

art]ies4 ,x encloses ^!1 & is atta*$ to 
! sple51 pancreas1 /oma*1 & ant]ior end 
( ! inte/9e4  ,! sple5 is connect$ ) !  
/oma* by ! ga/ro-spl5ic om5tum1 =m$ by  
an ext5sion ( ! p]itoneal coat ( ! /oma*
 ar\nd ! sple54 ,! liv] is connect$ to !
 loop ( ! /oma* by ! ga/ro-hepatic      
om5tum 9 :i* are ! hepatic duct1 portal 
ve91 & hepatic art]y4 ,ne> ! /oma* x is 
jo9$ by a fold ( ! p]itoneum f !        
duod5um1 ! duod5o-hepatic om5tum1 :i*   
also unites ) ! mesoga/]4  ,! rectum &  
rectal gl& are support$ by a second     
m$ian mes5t]y1 ! mesorectum4  ,9        
,eugaleus ! mes5t]y ext5ds ! entire l5g?
 ( ! abdom9al cavity4 ,x =ms a broad    
%eet atta*$ to ! ant]ior end ( !        
proximal limb ( ! /oma* 7mesoga/]71 to !
 ant]ior end ( ! inte/9e 7mes5t]y       
prop]71 & to ! rectum 7mesorectum74 ,!re
 is n ! r$uction ( ! mes5t]y :i* !re is 
9 ,squalus4 ,! gonads are susp5d$ f !   
lat]al faces ( ! mes5t]y above ! /oma* &
 inte/9e4 ,! ga/ro-hepatic om5tum =ms a 
broad %eet betwe5 ! limbs ( ! /oma*1    

jo9+ ! mesoga/] dorsal to ! /oma* & !   
mes5t]y above ! inte/9e4  ,a small      
division ( ! "r lobe ( ! liv] /&s out   
betwe5 ! ma9 lobes4 ,9 ?is is locat$ a  
long1 n>r[ gall-bladd]4 ,op5 ! bladd] by
 a longitud9al v5tral incision4 ,! op5+ 
into ! bile duct w be f\nd ne> ! ant]ior
 end ( ! bladd]4  ,9 ,eugaleus1 :i* does
 n possess su* a m$ian lobe1 !          
gall-bladd] lies hidd5 9 ! "r lobe ( !  
liv]4 ,x c be op5$ & explor$1 b !       
connection ) ! duct c usually be        
demon/rat$ only by scrap+4 ,d ?is lat]4 
,! bile duct passes along ! dorsal side 
( ! gall-bladd] & ! edge ( !            
ga/ro-hepatic & duod5o-hepatic om5ta to 
! junction ( ! duod5um & l>ge inte/9e1  
:]e x op5s into ! alim5t>y canal4 ,trace
 its oblique c\rse ?r\gh ! wall ( !     
inte/9e4 ,! bile duct & ! collect+      
7hepatic7 ducts ( ! liv] w be trac$ 9 ! 
liv] at a lat] /age ( ! dissection4  ,! 
pancreas consi/s ( two lobes2 a sl5d]   
lobe ly+ dorsal to & p>allel ) ! /oma*1 
& a flatt5$ oval lobe ly+ ^u ! v5tral   

surface ( ! duod5um1 connect$ ) ! dorsal
 lobe by a sl5d] b> ( gl&ul> tissue4  ,!
 pancreatic duct passes f ! extreme "r  
end ( ! duod5al lobe obliquely ?r\gh !  
wall ( ! inte/9e1 op5+ into ! ant]ior   
end ( ! l>ge inte/9e4 ,free ! edge ( !  
lobe f ! p]itoneum & foll[ ! duct4  ,op5
 ! proximal limb ( ! /oma* by a v5tral  
incision :i* %all n cut any l>ge blood  
vessels4 ,wa% out ! int]ior4 ,obs]ve !  
?ree coats ( ! /oma*2 ! out] p]itoneal1 
! middle muscul>1 & ! inn] muc\s coats4 
,9 ! ant]ior portion ( ! /oma* ! muc\s  
coat projects 9 ! =m ( l>ge papillae    
7abs5t 9 ,eugaleus74 ,po/]ior to ^!1    
obs]ve ! irregul> fold+ ( ! muc\s coat1 
dep5d+ ^u ! degree ( contraction ( !    
muscul> coat4  ,! muscul> coat consi/s (
 an out] circul> & an inn] longitud9al  
lay] ( muscle fibres4 ,sep>ate ! two    
lay]s f ea* o!r & f ! muc\s coat2 obs]ve
 ! network ( blood vessels betwe5 !     
longitud9al muscles & ! mucosa4  ,op5 ! 
pyloric end ( ! /oma*1 cont9u+ ! cut    
?r\gh ! pylorus into ! inte/9e4 ,exam9e 

! coats z be=e1 obs]v+ especially t an  
out] lay] ( longitud9al muscle fibres is
 frequ5tly develop$1 & t ! pyloric valve
 is =m$ by an increase 9 ! ?ickness ( ! 
coat ( circul> fibres4  ,cut ?r\gh !    
wall ( ! l>ge inte/9e along ! "r side f 
its ant]ior end to ! rectum4 ,d n cut   
deep] ?an ! ?ickness ( ! wall4          
,correspond+ to ! ext]nal m>k+s1 ! muc\s
 membrane projects int]nally 9 a spiral 
fold1 kn[n z ! spiral valve4 ,sep>ate ! 
wall ( ! inte/9e f ! edge ( ! spiral    
fold ^u bo? sides ( ! longitud9al       
incision1 expos+ a consid]able surface (
 ! valve4 ,wa% well1 & obs]ve ! "* ( !  
valve1 ! direction ( ! folds1 & ! mann] 
( ! rev]sal ( _! direction :i* usually  
takes place 9 ! po/]ior half ( ! valve4 
,cut across ! rectal gl& at its middle4 
,obs]ve ! "* ( its tissues1 & !n ins]t a
 bri/le into ! c5tral cavity ( ! gl& &  
pass x into ! rectum4 ,op5 ! rectum &   
note ! po9t ( communication ( ! two     
organs4  ,,ur9>y ,,& ,,reproductive     
,,organs4 ,! kidneys 7mesonephri1       

,wolffian bodies71 are sl5d] bodies     
ext5d+ along ! entire l5g? ( ! dorsal   
wall ( ! abdom54 ,! po/]ior moiety ( ea*
 is ?ick] & wid] ?an ! ant]ior1 :i*     
appe>s to h l>gely lo/ ! functions (    
excretion 9 adult dogfi%4 ,notice !     
position ( ! kidneys outside !          
p]itoneum4  ,,! ,,male4 ,! te/es are    
:ite bodies ly+ to ! "r & left ( !      
oesophagus1 dorsal to ! ant]ior portion 
( ! liv]4 ,ea* is susp5d$ by a fold ( ! 
p]itoneum1 ! mesor*ium4 7,! te/es (     
,galeus are long bodies atta*$ to !     
sides ( ! mes5t]y47  ,%[+ ?r\gh !       
p]itoneum1 a mu* convolut$1 :ite tube c 
be se5 on ! v5tral surface ( ! kidney4  
,?is is ! mesonephric or ,wolffian duct4
 ,9 "y specim5s x may be ne>ly /raight1 
ly+ ne> ! m$ial bord] ( ! kidney4 ,9    
adult specim5s x c be foll[$ =w>d z f> z
 ! ant]ior end ( ! te/is4 ,:ile !       
,wolffian duct is ! duct ( ! kidney1 &  
is jo9$ by tubules ( ! ant]ior "p ( !   
kidney1 x is s modifi$ 9 ! male t its   
pr9cipal function is to s]ve z ! duct ( 

! te/is1 a vas def]5s4 ,! collect+      
tubules ( ! po/]ior "p ( ! kidney jo9 to
 =m a ur9>y duct :i* is indep5d5t ( !   
,wolffian duct4 ,! po/]ior end ( !      
,wolffian duct is /raight & consid]ably 
exp&$1 =m+ a l>ge sem9al vesicle4 ,!    
duct becomes m & m closely convolut$ z x
 passes =w>d1 & ! kidney tissue ov]ly+ x
 dim9i%es4 ,at ! ant]ior end ( !        
mesonephros ! ,wolffian duct =ms a mass 
( tubules1 ! epididymis4 ,v small       
tubules1 ! vasa eff]5tia1 pass f !      
ant]ior end ( ! te/is to ! epididymis4  
,^! are difficult = ! /ud5t to di/+ui%4 
,cut ?r\gh ! p]itoneum along ! out] side
 ( "o kidney4 ,!n /rip ! p]itoneum t[>d 
! inn] bord] ( ! kidney4 ,! ur9>y duct w
 usually be closely atta*$ to !         
p]itoneum & p>allel ) ! ,wolffian duct1 
b ne>] ! midl9e ( ! body4 ,! ur9>y duct 
c be sep>at$ f ! p]itoneum by a little  
c>eful "w4 ,num]\s small ducts pass f ! 
kidney into ! ur9>y duct4  ,op5 !       
uro-g5ital papilla ne> its tip & ext5d !
 incision =w>d s z to op5 ! sac connect$

 ) ! base ( ! papilla4 ,! pore at ! tip 
( ! papilla leads into a space )9 !     
papilla itself1 ! uro-g5ital s9us1 :i*  
bran*es to ! left & "r 9 p\*es :i* ext5d
 beyond ! po/]ior ends ( ! vasa         
def]5tia4 ,^! cornua ( ! uro-g5ital s9us
 are ( v>iable l5g?1 & are (t5 nam$     
sp]m-sacs4 ,9 a mature male !y may be   
f\nd to be fill$ ) sp]m1 z may also !   
sem9al vesicles & ! convolut$ portion ( 
! ,wolffian duct4 ,! op5+s ( ! vasa     
def]5tia into ! s9us are l>ge & easily  
locat$4 ,! ur9>y duct op5s into ! s9us  
by a sep>ate pore j beh9d ! op5+ ( ! vas
 def]5s4  ,cut op5 ! sem9al vesicle & "p
 ( ! convolut$ vas def]5s4 ,! space )9  
is subdivid$ by transv]se folds or      
lamellae ext5d+ f a longitud9al ridge4  
,no vasa eff]5tia c be di/+ui%$ 9       
,eugaleus4 ,! ant]ior extremities ( !   
kidney & te/is ( ea* side come into     
close contact ) ea* o!r & "h ! vasa     
eff]5tia pass f ! te/is to ! vas def]5s4
 ,! sp]m-sac is a l>ge bl9d p\*1 "o or  
two in*es 9 l5g?1 lead+ out ( ! po/]ior 

end ( ! vas def]5s1 & direct$ =w>d along
 its side4 ,! vas def]5s ( ,eugaleus is 
n convolut$4  ,9 ! "y specim5s usually  
suppli$ to laboratories ! vas def]5s is 
/raight & no sem9al vesicle is develop$4
 ,! vasa eff]5tia are m difficult to    
see2 o!rwise ! relations ( ! ur9>y &    
g5ital organs are z 9 ! adult4  ,!      
susp5sory ligam5t ( ! liv] is cont9u$   
po/]iorly along ! midl9e ( ! v5tral body
 wall2 ! dorsal edge supports a funnel  
:i* op5s into ! abdom9al cavity by a    
long1 n>r[ m\?4 ,f ! ant]ior end ( !    
funnel two n>r[ tubes pass to ! "r &    
left ov] ! ant]ior surface ( ! liv]4 ,!y
 end bl9dly 9 ! tissues dorsal to !     
ant]ior end ( ! liv]4 ,^! are ve/iges ( 
! ,muell]ian ducts 7pronephric ducts7   
:i* =m ! oviducts ( ! females4  ,,!     
,,female4 ,! ov>ies are l>ge1 :ite      
bodies ly+ at ! sides ( ! /oma*1 dorsal 
to ! lobes ( ! liv]4 ,ea* is cov]$ by ! 
p]itoneum & susp5d$ by a fold ( ! same1 
! mesov>ium4 ,ova ( v>i\s sizes may be  
felt 9 ! tissue ( ! ov>y1 :i* %\ld be   

expos$ by dissection4  ,! ov>ies (      
,eugaleus are long sl5d] bodies ly+ on  
ei!r side ( ! mesoga/]1 dorsal to !     
/oma* & inte/9e4 ,_! po/]ior portions   
are fus$4  ,! oviducts 7,muell]ian      
ducts7 are l>ge tubes susp5d$ f betwe5 !
 kidneys by a n>r[ p]itoneal b&4 ,!     
po/]ior portion ( ! oviduct1 :]e        
developm5t ( ! eggs takes place1 is     
consid]ably enl>g$4 ,ea* oviduct op5s   
sep>ately into ! cloaca by a pore at !  
side ( ! ur9>y papilla4 ,foll[$ =w>d1 ! 
oviducts pass ov] ! ant]ior surface ( ! 
liv] & foll[+ a cont9uation ( !         
susp5sory ligam5t1 b5d ar\nd po/]iorly &
 unite4 ,at ! po9t ( union !y op5 into !
 coelom by a common1 l>ge1 funnel-%ap$  
ap]ture1 ! o/ium tubae4  ,cut ?r\gh !   
p]itoneum along ! out] side ( "o kidney4
 ,!n /rip ! p]itoneum t[>d ! inn] side (
 ! kidney4 ,num]\s small excretory ducts
 w be se5 jo9+ ! ma9 ur9>y duct         
7,wolffian duct1 mesonephric duct71 :i* 
runs along ! inn] m>g9 ( ! kidney4 ,make
 an incision 9 ! side ( ! ur9>y papilla 

to op5 ! cavity )9 x1 ! ur9>y s9us4 ,!  
connection ( ?is ) ! pore at ! tip ( !  
papilla %\ld be demon/rat$4 ,ext5d !    
incision =w>d4 ,! ur9>y s9us divides    
into "r & left cornua :i* are (         
consid]able size & lie dorsal to !      
oviducts4 ,trace ! ,wolffian duct to !  
ur9>y s9us & demon/rate its op5+ into ! 
cornu ant]ior to ! po9t :]e ! two cornua
 unite4  ,9 "y specim5s ! ov>ies are    
small1 & ! oviducts are n>r[1 :ite tubes
 ly+ along ! m$ial m>g9s ( ! kidneys4   
,nephro/omes1 %ort1 segm5tally arrang$  
kidney tubules :i* op5 to ! coelom by a 
funicul> ap]ture1 are f\nd by a close   
exam9ation along ! m$ial bord] ( ea*    
kidney4 ,!y %\ld be obs]v$ c>efully ) ! 
aid ( a good dissect+ l5s4 ,le>n !      
significance ( ^! /ructures4  ,9 ! c\rse
 ( developm5t two sets ( nephridia      
7kidneys7 are =m$4 ,! fir/ 7pronephros7 
develops j back ( ! head ( ! embryo1 b  
does n p]si/ 9 ! adult4 ,its duct1 kn[n 
commonly z ! ,muell]ian duct1 develops  
into ! functional oviduct ( ! female1 b 

=ms an app>5tly useless ve/ige 9 ! male4
 ,! second kidney 7mesonephros7 develops
 beh9d ! fir/ & is ! excretory organ ( !
 adult4 ,its duct 7frequ5tly giv5 ! "n (
 ,wolffian duct7 is ! ur9>y duct 9 !    
female1 b functions 9 ! male *iefly z a 
sp]m duct1 & !re=e is call$ ! vas       
def]5s4 ,! collect+ tubules ( ! po/]ior 
portion ( ! kidney ( ! male unite to =m 
a ur9>y duct :i* op5s into ! ,wolffian  
duct or ! uro-g5ital s9us4              
,,respiratory ,,organs  ,op5 ! ant]ior  
gill p\* ( ! left side by dorsal &      
v5tral cuts ext5d+ f ! angles ( ! cleft1
 b cutt+ only z f> z is necess>y to see 
! /ructures )9 ! p\*4 ,^u ! m$ial side !
 gill p\* op5s into ! ph>ynx by a       
dorso-v5tral slit1 gu>d$ by project+    
c>tilag9e\s gill rak]s1 :i* prev5t      
p>ticles ( food f pass+ into ! gill p\* 
) ! respiratory curr5t4 ,on bo? !       
ant]ior & po/]ior wall ( ! p\* is a     
demibran*4 ,if ! specim5 is inject$ a   
l>ge blood vessel c be se5 ?r\gh ! sk9 9
 ! inn] bord] ( ! demibran*1 & small    

vessels pass+ f ?is into ! leaflets1 :]e
 ! int]*ange ( gases betwe5 ! wat] &    
blood takes place4  ,op5 simil>ly ea*   
p\* ( ! same side1 obs]v+ ! numb] ( !   
demibran*s & _! relation to ! p\*es4    
,^u ! ant]ior wall ( ! spiracle         
demon/rate a r[ ( small ve/igial gills2 
be+ suppli$ ) art]ial in/ead ( v5\s     
blood !y =m :at is t]m$ a pseudobran*4  
,,vascul> ,,sy/em  ,,he>t ,,& ,,v5tral  
,,aorta4 ,cont9ue ! longitud9al incision
 ?r\gh ! sk9 z f> z ! m&ible4#a ,dissect
 away ! %eet ( muscles betwe5 ! gill    
p\*es & ! m&ible1 expos+ a sl5d] muscle 
:i* ext5ds f ! pectoral girdle to !     
middle ( ! m&ible4 ,! ?yroid gl& lies   
dorsal to ! ant]ior end ( ?is muscle1   
close aga9/ ! m&ible4 7,! ?yroid (      
,eugaleus is a broad1 flatt5$ /ructure  
cov]+ ! ant]ior ends ( ! coracohyoideus 
muscles47 ,c>efully dissect out !       
muscles ly+ betwe5 ! bran*ial p\*es ( ! 
"r & left sides4  ,footnote #a3    ,see 
footnote1 p4 #ca4  ,9 front ( ! pectoral
 girdle lies a ?9-wall$ sac1 ! p]ic>dial

 sac4 ,op5 x by a m$ian v5tral incision4
 ,remove ab\t "o-half in* ( ! middle ( !
 pectoral girdle1 be+ c>eful n to cut ! 
?9-wall$ "p ( ! he>t ly+ dorsal to x4 ,!
 p]ic>dial cavity is a pe>-%ap$ *amb]   
conta9+ ! he>t1 & l9$ by ! smoo?        
p]ic>dium :i* is morphologically        
equival5t to ! p]itoneum4 ,at ! ant]ior 
extremity ( ! *amb] ! p]ic>dium is se5  
to be reflect$ backw>d ov] ! surface ( !
 he>t1 ?us =m+ its smoo? out] coat4  ,! 
he>t may be consid]$ z a b5t tube1      
enl>g$ 9 c]ta9 regions to =m ! *amb]s4  
,ant]iorly & v5trally is a %ort1        
?ick-wall$ tube1 ! conus art]iosus2 ?is 
leads out ( ! p]ic>dial sac ant]iorly1  
:ile po/]iorly x op5s into a l>ge       
muscul> *amb]1 ! v5tricle4 ,dorsal to ! 
v5tricle1 & project+ on ei!r side ( x is
 ! ?9-wall$ auricle4 ,dorsal to bo?     
v5tricle & auricle is ! extremely       
?9-wall$ s9us v5osus4 ,?is is triangul> 
9 %ape1 ! apex op5+ into ! po/]ior side 
( ! auricle1 ! base atta*$ to ! po/]ior 
wall ( ! p]ic>dial cavity2 ! lat]al     

angles are drawn out into ! ducti       
cuvi]ii1 :i* receive ve9s f ! ant]ior & 
po/]ior p>ts ( ! body4 ,f ! conus       
art]iosus spr+s a small] vessel1 !      
v5tral aorta1 :i* passes =w>d betwe5 !  
gill p\*es4 ,take note ( ! small art]ies
 pass+ ov] ! surface ( ! conus & along !
 inn] ends ( ! gill p\*es1 & take c>e n 
to cut !m or _! bran*es 9 ! subsequ5t   
dissection4  ,two pairs ( art]ies leave 
! v5tral aorta z x em]ges f ! p]ic>dial 
sac4 ,! aorta !n passes =w>d "s di/ance 
& f9ally divides into two bran*es :i*   
pass to ei!r side4 ,foll[ ! bran*es ( ! 
aorta outw>d on ! left side & demon/rate
 _! c\rses4 ,! ant]ior bran* quickly    
divides into two1 ! ant]ior ( ^! pass+  
along ! base ( ! fir/ demibran*4 ,!     
po/]ior ent]s ! septum betwe5 ! fir/ &  
second p\*es1 & supplies ! second & ?ird
 demibran*s4 ,! middle bran* ( ! aorta  
passes directly to ! f\r? & fif?        
demibran*s4 ,! po/]ior bran* divides    
almo/ z x leaves ! aorta1 its bran*es   
supply+ ! rema9+ demibran*s4 ,!re is    

consid]able v>iation 9 ?is bran* ( !    
aorta4 ,x usually divides z /at$1 b x   
frequ5tly passes "s di/ance t[>d ! gills
 be=e divid+1 & 9 a consid]able numb] ( 
cases two vessels arise directly f !    
aorta in/ead ( "o4  ,! art]ies c>ry+    
blood f ! v5tral aorta to ! gills are   
nam$ ! aff]5t bran*ial art]ies4 ,obs]ve 
! relation ( ^! vessels to ! gills4     
,,v5\s ,,sy/em4 ,all ! blood ( ! body is
 convey$ to ! s9us v5osus4 ,! sides ( ! 
s9us v5osus are ext5d$ z l>ge vessels1  
already ref]r$ to z ! ducti cuvi]ii4    
,op5 ! s9us & ducti by a transv]se      
v5tral incision4 ,! ducti pass directly 
into ! lat]al ve9s4 ,ne> ! middle ( !   
po/]ior wall ( ! s9us is an ap]ture (   
v>y+ size1 ! op5+ ( ! hepatic s9us2 !re 
are r>ely two op5+s 9 ,squalus1 always  
two 9 ,eugaleus4 ,a l>ge op5+ on !      
po/]ior wall ( ea* ductus leads into !  
po/]ior c>d9al ve94 ,on ! ant]ior wall (
 ! ductus1 ne> ! s9us v5osus1 is a small
 ap]ture1 t ( ! inf]ior jugul> ve94     
,lat]al to ?is is frequ5tly a some:at   

l>g] op5+ ( ! ant]ior c>d9al ve94 ,?is  
is abs5t1 h[ev]1 9 ! majority (         
specim5s2 ! ant]ior c>d9als op5+ into ! 
ant]ior ends ( ! po/]ior c>d9als 9 ab\t 
six out ( t5 cases4  ,a l>ge cavity1 !  
hepatic s9us1 exi/s 9 ! ant]ior end ( ! 
liv] j po/]ior to ! susp5sory ligam5t4  
,cut into ! liv] at ?is po9t until !    
s9us is f\nd1 op5 x1 & obs]ve ! l>ge    
hepatic ve9s br++ blood into x f ! liv]1
 z well z its communication ) ! s9us    
v5osus4  ,trace all ve9s by pass+ a     
flexible probe or gu>d$ bri/le along !m 
& !n op5+ ! ve9 ) ! probe z a guide4    
,all small] vessels empty+ into ^?      
describ$ %\ld be not$4  ,! lat]al ve9s  
pass =w>d to ! po/]ior edge ( ! pectoral
 girdle1 b5d %>ply dorsad1 & ent] !     
lat]al extremities ( ! ducti cuvi]ii4   
,op5 a lat]al ve9 ne> ! ant]ior end &   
trace x t[>d ! he>t4 ,! "r & left lat]al
 ve9s are jo9$ by a ve9 pass+ along !   
v5tral b> ( ! pectoral girdle4 ,op5 !   
lat]al ve9s at a po9t ab\t two in*es 9  
front ( ! pelvic girdle & trace ! ve9s  

backw>d z f> z !y c be foll[$4 ,! blood 
f ! pelvic f9s ent]s ! lat]al ve9 ?r\gh 
! femoral ve94 ,! lat]al ve9s f9ally    
unite back ( ! cloaca4  ,j be=e ! lat]al
 ve9 ent]s ! ductus cuvi]ius x is jo9$  
by a l>ge coracoid ve9 :i* runs dorsad &
 po/]iorly along ! po/]ior edge ( !     
pectoral ar*4 ,foll[ its c\rse4 ,x      
receives a good-siz$ pectoral ve9 f !   
pectoral f91 & sometimes sev]al small]  
ve9s f ! same region4 ,trac$ dorsad x is
 f\nd to op5 into a l>ge blood s9us     
above ! liv] & oesophagus1 ! c>d9al     
s9us4  ,9 ,eugaleus ?is connect+ ve9    
betwe5 ! lat]al ve9 & ! c>d9al s9us is  
want+1 ! pectoral ve9 op5+ directly into
 ! lat]al4  ,! v5tral cutane\s ve91 :i* 
runs along ! v5tral midl9e ( ! body     
wall1 %\ld be foll[$2 ant]iorly x jo9s !
 vessel unit+ ! two lat]als2 po/]iorly x
 divides at ! pelvic ar* & ana/omoses ) 
! lat]als4  ,pass a bri/le f ! s9us     
v5osus into "o ( ! po/]ior c>d9al ve9s &
 trace ! ve9 backw>d betwe5 ! kidneys z 
f> z possible4 ,op5 bo? po/]ior c>d9als 

9 ?is way1 wa%+ !m out & obs]v+ t !y    
receive blood f ! kidneys by a s]ies (  
r5al ve9s1 & t !y are sep>ate 9 _!      
po/]ior p>ts1 b communicate ) ea* o!r   
ant]iorly1 :]e !y are greatly exp&$2 !  
communicat+ portions & co9cid5t         
enl>gem5t =m+ ! c>d9al s9us4 ,! ant]ior 
portion ( ! c>d9al ve9 receives ov>ian  
or sp]matic ve9s f ! female or male     
gonad1 ant]ior oviducal ve9s f ! ant]ior
 "p ( ! oviduct1 & segm5tal ve9s f !    
correspond+ region ( ! body wall4 ,!re  
sometimes is m ?an a s+le op5+ f !      
po/]ior c>d9al ve9 into ! cuvi]ian duct4
  ,cut across ! tail an in* beh9d !     
cloaca4 ,two vessels lie 9 ! c>tilag9\s 
ar* bel[ ! c5tra ( ! v]tebrae2 ! dorsal 
( ! two is ! caudal art]y1 ! v5tral "o  
is ! caudal ve94 ,foll[ ! ve9 =w>d4     
,dorsal to ! cloaca x divides into two1 
:i* %\ld be foll[$ along ! dorsal       
surfaces ( ! kidneys4 ,^! are ! r5al    
portal ve9s1 convey+ blood to ! kidneys4
 ,besides collect+ ! blood ( ! tail !   
r5al portals also receive ! po/]ior     

oviducal & segm5tal ve9s4 ,!y pass into 
! capill>ies ( ! kidneys4  ,! inf]ior   
jugul> ve9 op5s into ! m$ial end ( !    
cuvi]ian duct4 ,trace x =w>d along !    
v5tral ends ( ! gill p\*es2 x receives  
vessels f ! ar*es & f9ally jo9s !       
hyoidean ve9s :i* foll[ ! hyoid ar*4 ,at
 ! out] end ( ! cuvi]ian duct !re is (t5
 a small op5+ on ! ant]ior wall opposite
 ! m\? ( ! po/]ior c>d9al ve94 ,?is     
leads into ! ant]ior c>d9al ve94 ,z     
m5tion$ be=e1 9 a slight majority ( !   
cases exam9$1 ! ant]ior c>d9al ve9 op5s 
into ! po/]ior c>d9al ve91 n directly   
into ! cuvi]ian duct4 ,if possible1 pass
 a bri/le into ! ant]ior c>d9al4 ,to    
foll[ ! ve91 & usually ?is is ! be/ way 
to f9d x1 make a v]tical longitud9al    
incision ^u ! dorsal side ( ! neck1     
betwe5 ! gill p\*es & ! mass ( muscle   
ly+ beside ! v]tebral column4 ,?is w op5
 ! ant]ior c>d9al1 :i* is consid]ably   
exp&$ 9 ?is region1 & x may be trac$ f  
?is po9t t[>d ! he>t & ! head4 ,!       
ant]ior c>d9al n>r[s sudd5ly 9 front ( !

 ant]ior gill p\*1 & leads d[nw>d to !  
orbit1 :]e x exp&s into ! orbital s9us  
surr\nd+ ! eyeball & its muscles4 ,trace
 ! ant]ior c>d9al only z f> z ! op5+    
into ! orbital s9us at ?is "t4 ,ve9s f !
 ant]ior portion ( ! head & f ! bra9 c  
be foll[$ :5 ! dissection ( ! eye is    
und]tak54  ,j back ( ! spiracle !       
ant]ior c>d9al receives ! hyoidean ve91 
:i* passes v5trad along ! base ( ! fir/ 
demibran* & unites ) ! hyoidean ( !     
opposite side4 ,v5trally1 x also        
communicates ) ! inf]ior jugul> ve94  ,!
 pr9cipal ve9s ( ! body h n[ be5        
dissect$ ) ! exception ( ! hepatic      
portal ve91 :i* x is bett] to trace aft]
 ! art]ies ( ! dige/ive tract h be5     
/udi$4  ,,! ,,eff]5t ,,bran*ial         
,,art]ies ,,& ,,dorsal ,,aorta4 ,comm5c+
 at ! m\?1 cut ?r\gh ! floor ( ! ph>ynx 
close to ! left side ( ! v5tral aorta & 
! he>t4 ,! cut %\ld leave ! gill ar*es  
un9jur$1 & may be cont9u$ into !        
oesophagus4  ,exam9e ! int]ior ( ! m\? &
 ph>ynx1 obs]v+ p>ticul>ly ! =m &       

arrangem5t ( ! tee?1 ! spiracul> &      
bran*ial clefts1 ! gill rak]s1 & ! "* ( 
! muc\s coat ( ! ph>ynx4  ,remove ! sk9 
f ! ro( ( ! ph>ynx4 ,?is exposes f\r    
pairs ( eff]5t bran*ial art]ies br++    
blood f ! gills & unit+ 9 pairs to =m ! 
dorsal aorta4 ,foll[ ea* vessel ( ! left
 side out to its gill-cleft4 ,at !      
dorsal end ( ! gill-cleft x divides into
 a l>ge po/]ior & small ant]ior bran*4  
,^! respectively pass along ! po/]ior & 
ant]ior demibran*s ( ! gill p\*1 receiv+
 f9e bran*es f ! gill lamellae1 & f9ally
 unite aga9 at ! v5tral end ( ! gill    
p\*4 ,?us a complete loop is =m$ ar\nd !
 bran*ial cleft4 ,! po/]ior bran* ( ea* 
eff]5t art]y & ! ant]ior bran* ( !      
succe$+ "o are unit$ by sev]al %ort     
vessels4 ,! eff]5t art]y ( ! la/        
demibran* possesses only ^! connections 
) ! bran* next ant]ior to x1 & none ) ! 
aorta directly4 ,f ! v5tral ends ( !    
eff]5t loops small vessels pass t[>d !  
midl9e to unite ) a longitud9al art]y1 !
 hypobran*ial art]y1 :i* w be trac$ f>!r

 a little lat] 9 ! dissection4  ,9      
,eugaleus ! dorsal aorta ext5ds =w>d    
beyond ! union ( ! fir/ pair ( eff]5t   
bran*ials & !n divides into small "r &  
left bran*es :i* pass =w>d & outw>d to  
unite ) ! common c>otid art]ies4  ,a    
common c>otid art]y leaves ! dorsal end 
( ea* ant]ior eff]5t bran*ial loop1     
pass+ =w>d & inw>d4 ,at ! level ( !     
spiracles x divides into ext]nal &      
int]nal c>otids2 ! int]nal c>otid unites
 ) its fell[ ( ! opposite side & ent]s !
 skull4 ,! ext]nal c>otid art]ies run   
outw>d & =w>d ar\nd ! eyes & are        
di/ribut$ to ! regions ( ! m&ible &     
sn\t4 ,d n1 at pres5t1 trace !m beyond !
 po/]ior edge ( ! eye4  ,ano!r vessel   
arises f ! middle ( ! ant]ior side ( !  
fir/ eff]5t bran*ial loop & runs =w>d to
 ! spiracle1 :]e x ends 9 ! capill>ies (
 ! pseudobran*4 ,?is is ! aff]5t        
hyoidean art]y4 ,! t]m pseudobran* is   
us$ = ! bran*ial lamellae ( ! spiracle r
 ?an demibran* because ( ! art]ial blood
 supply ( ?is organ4  ,imm$iately aft]  

unit+ ! int]nal c>otids divide & div]ge1
 =m+ an ,x-%ap$ figure4 ,ea* ant]ior    
limb ( ! ,x aga9 divides into two       
bran*es4 ,! lat]al bran* passes to !    
v5tral surface ( ! skull2 x pres5tly    
gives (f an ant]ior twig 7oph?almic     
art]y7 :i* ent]s ! eye4 ,x !n passes on 
z ! eff]5t hyoidean art]y to !          
pseudobran*4 ,! inn] ( ! two bran*s     
m5tion$ above passes on z ! int]nal     
c>otid1 s5su /rictu1 & is di/ribut$ to !
 bra94  ,if ! dissection is made ) c>e1 
! bran*es ( ! int]nal c>otid c all be   
f\nd )\t cutt+ any important n]ves4 ,!  
bran*es pass+ to ! eye & bra9 are be/   
trac$ to _! t]m9ations 9 connection ) ! 
dissection ( ! n]v\s sy/em4  ,ne> !     
union ( ! fir/ pair ( eff]5t bran*ial   
art]ies a small po/]ior v]tebral art]y  
arises f ea*1 & runs ant]iorly along !  
v]tebral column4  ,ne> ! divisions ( !  
common c>otids two ant]ior v]tebral     
art]ies arise f ^! vessels & pass       
po/]iorly1 (t5 ana/omos+ ) ! po/]ior    
v]tebral art]ies4 ,^! v]tebral art]ies  

are ve/iges ( ! =m] ant]ior "p ( !      
dorsal aorta 7comp>e ) ,eugaleus1 9 :i* 
! dorsal aorta s5ds =w>d two vessels :i*
 jo9 ! common c>otids74  ,an oesophageal
 art]y spr+s f ! second eff]5t bran*ial1
 & passes back until x ent]s ! wall ( ! 
oesophagus4 ,x also gives (f nutri5t    
bran*es to ! second1 ?ird1 & f\r? gill  
p\*es4 ,! nutri5t art]y ( ! fir/ gill   
p\* arises directly f ! fir/ eff]5t     
bran*ial4  ,ne> ! po9t at :i* ! f\r?    
pair ( eff]5t bran*ials jo9 ! aorta1 two
 small subclavian art]ies leave ! aorta 
& pass into ! pectoral f9s4 ,!re is "s  
v>iation 9 reg>d to ! po9t ( orig9 ( ^! 
vessels2 x may be ei!r 9 front ( or     
beh9d ! junction ( ! f\r? eff]5t        
bran*ials ) ! aorta4  ,! hypobran*ial   
art]y passes along ! v5tral ends ( !    
gill p\*es4 ,x is ei!r connect$ ) !     
eff]5t bran*ial loops by %ort bran*es1  
or is =m$1 9 "p at lea/1 by %ort vessels
 connect+ ^! loops4 ,! hypobran*ials are
 important nutri5t vessels1 supply+ !   
gill p\*es & ! muscles ( ! ?roat & !    

oesophagus by means ( num]\s small      
art]ies2 f ! hypobran*ials also arise   
small po/]ior coron>y art]ies :i* pass  
to ! v5tral & po/]ior walls ( !         
p]ic>dium & ! s9us v5osus1 & l>g]       
ant]ior coron>y art]ies supply+ !       
v5tricle & conus art]iosus4 ,!          
hypobran*ials c frequ5tly he foll[$     
along ! dorsal side ( ! p]ic>dium & !n  
outw>d to junctions ) ! subclavian      
art]ies4  ,! coeliac art]y 7coeliac     
axis7 arises f ! aorta j back ( !       
subclavians4 ,pass+ po/]iorly & v5trad  
close to ! "r side ( ! /oma* & rea*+ !  
ga/ro-hepatic om5tum1 x divides into two
 bran*es1 ! ga/ro-hepatic & ant]ior     
inte/9al art]ies4 ,! fir/ gives (f a    
small hepatic art]y to ! liv] & a l>ge  
ga/ric art]y to ! c>diac limb ( ! /oma*4
 ,! ant]ior inte/9al art]y supplies !   
pyloric limb ( ! /oma*1 ! pancreas1     
duod5um1 & "r side ( ! l>ge inte/9e4    
,small g5ital art]ies1 supply+ !        
reproductive gl&s1 arise f ! coeliac ne>
 its orig94 7,9 ,eugaleus ! g5ital      

art]ies arise f ! ant]ior & po/]ior     
mes5t]ic art]ies47  ,at ab\t ! middle ( 
! abdom9al cavity two art]ies arise     
close toge!r f ! aorta4 ,! ant]ior ( !  
two is ! ant]ior mes5t]ic art]y2 x      
passes to ! left side ( ! l>ge inte/9e &
 its bran*es ana/omose m or less ) ^? ( 
! ant]ior inte/9al art]y4 ,! po/]ior    
vessel is ! li5oga/ric2 x goes to !     
sple51 pancreas1 & loop ( ! /oma*4  ,!  
po/]ior mes5t]ic art]y leaves ! aorta a 
little di/ance back ( ! li5oga/ric &    
passes to ! rectal gl&1 rectum1 &       
cloaca4  ,free ! kidney f ! body wall   
along its out] edge & turn x up s z to  
expose its dorsal surface4 ,obs]ve !    
num]\s p>ietal art]ies 7go+ to ! body   
wall7 & r5al art]ies 7to ! kidney71 :i* 
spr+ f ! dorsal aorta4 ,bran*es ( !     
p>ietals also pass into ! kidney4  ,a   
pair ( small iliac art]ies pass into !  
pelvic f9s4  ,oviducal art]ies1 "o or   
sev]al on ea* side1 arise f ! aorta     
beh9d ! coeliac art]y & pass to !       
oviduct4 ,_! size v>ies l>gely ) !      

developm5t & physiological condition ( !
 oviduct4  ,! aorta is cont9u$ 9 ! tail 
z ! caudal art]y4  ,,dissection ,,( ,,! 
,,he>t4 ,remove ! he>t toge!r ) ! v5tral
 aorta f ! body & fa/5 x1 dorsal side   
up1 "u wat]4 ,op5 ! s9us v5osus )       
scissors1 wa% x out1 & obs]ve ! v]tical 
slit-l op5+ into ! auricle & ! two      
membrane\s valves :i* gu>d x4  ,cont9ue 
! cut ?r\gh ! s9u-auricul> ap]ture along
 ! m$ian dorsal l9e ( ! auricle2 obs]ve 
! ?9 walls ( ! auricle & _! /r5g!n+ by  
an irregul> me% ( muscles1 ! musculi    
pect9ati2 ! %ape & position ( !         
auriculo-v5tricul> ap]ture2 ! flaps ( ! 
auriculo-v5tricul> valve4 ,press ^u !   
sides ( ! v5tricle &1 if possible1      
obs]ve ! mode ( action ( ! valve4  ,cut 
across ! v5tricle f ! auriculo-v5tricul>
 ap]ture4 ,c>ry ano!r incision f ?is    
along ! dorsal side ( ! conus art]iosus4
 ,obs]ve ! small size ( ! cavity ( !    
v5tricle1 ! ?ickness ( its walls1 & !   
project+ network ( muscles1 ! columnae  
c>neae1 "s ( :i* are atta*$ to ! edges (

 ! auriculo-v5tricul> valves4  ,9 !     
conus art]iosus obs]ve ! r[s ( ?ree     
pocket-l valves ea* ar\nd ! proximal end
 7semilun> valves71 & a s+le r[ ( ?ree  
simil> b l>g] valves at ! junction ( !  
conus & v5tral aorta4 ,!re is "s        
v>iability 9 ! numb] ( r[s ( valves 9 ! 
conus ( ,squalus2 !re are always ?ree   
r[s ( ?ree valves ea* 9 t ( ,eugaleus4  
,9 ! aorta notice ! ap]tures )\t valves 
:i* lead into ! aff]5t bran*ial vessels4
  ,,hepatic ,,portal ,,sy/em4 ,! hepatic
 portal ve9 is ! l>ge ve9 ent]+ ! liv]  
alongside ! hepatic art]y & bile duct4  
,x receives bran*es f ! /oma*1 pancreas1
 sple51 inte/9e1 & rectal gl&4  ,at !   
surface ( ! liv] x divides into two     
bran*es1 :i* ent] ! two lobes ( ?is     
organ4 ,)9 ! liv] ! hepatic portal ve9s 
bran* until a capill>y sy/em is =m$ f   
:i* ! blood is collect$ by ! hepatic    
ve9s & c>ri$ into ! s9us v5osus4  ,9    
g5]al1 ! bran*es ( orig9 ( ! hepatic    
portal ve9 foll[ closely ! art]ies ( !  
dige/ive organs4 ,trace ! foll[+ p>ts ( 

! sy/em3 ,a po/]ior inte/9al ve91 f !   
rectal gl& & rectum1 ! l>ge inte/9e &   
spiral valve1 across to ! end ( !       
pancreas1 along ! pancreas to ! hepatic 
portal ve92 an ant]ior inte/9al ve91 f !
 l>ge inte/9e & spiral valve1 along !   
duod5al lobe ( ! pancreas2 ga/ric1      
duod5al1 & pyloric ve9s jo9+ ! ve9s     
already trac$2 a spl5ic ve9 jo9+ !      
po/]ior inte/9al ve94  ,! liv]1 ) ! bile
 duct1 may n[ be remov$ f ! body if x is
 desir$ to trace ! bile duct into !     
bladd] or to trace ! hepatic ducts4 ,?is
 c be done be/ by g5tly scrap+ away !   
s(t liv] tissue until ! bladd] & ducts  
are expos$4                             
,,! ,,n]v\s ,,sy/em4  ,only ! head &    
ant]ior "p ( ! trunk w be requir$ = !   
dissection ( ! n]v\s sy/em4 ,cut across 
! body back ( ! pectoral f9s2 ! po/]ior 
"p ( ! body w n be requir$ fur!r unless 
x is desir$ to /udy ! muscles &         
skeleton4  ,! mann] ( dissect+ ! bra9   
dep5ds some:at ^u ! specim5s at !       
disposal ( ! /ud5t4 ,if a l>ge head is  

to be us$ especially = ! dissection ( ! 
cranial n]ves1 only ! bra91 eye & e> ne$
 be /udi$ 9 ! pres5t specim54 ,b 9 mo/  
cases x w be f\nd be/ = ! /ud5t to      
dissect ! fir/ dogfi% z ?or\ghly z      
possible1 work+ out ! cranial n]ves z   
well z ! bra91 & res]v+ ! second head = 
a ?or\gh review ( ! entire n]v\s sy/em4 
,*apt] ,,iii ( ,h]rick & ,crosby's      
8,laboratory ,outl9e ( ,neurology0 %\ld 
be us$ 9 connection ) su* a review4  ,if
 a l9e be drawn ov] ! dorsal surface ( !
 head connect+ ! two spiracles1 two     
small pores w be f\nd ne> ! middle4 ,^! 
are ! ext]nal ap]tures ( ! ducti        
lymphatici4 ,cut c>efully ?r\gh ! sk9 9 
a small circle ar\nd ! pores1 & remove !
 sk9 f ! rema9d] ( ! dorsal surface ( ! 
skull )\t di/urb+ ! small section       
conta9+ ! pores4 ,! latt] "p %\ld n[ be 
lift$ g5tly2 b5ea? x w be se5 two       
delicate tubes pass+ f ! pores to       
ap]tures 9 a depression ( ! skull bel[  
!m4 ,^! tubes are ! ducti               
endolymphatici1 ?r\gh :i* a passage     

exi/s betwe5 ! int]nal e> & ! ext]ior4  
,z !y _c be pres]v$ 9 ! subsequ5t       
dissection1 ! pores by :i* !y pass ?r\gh
 ! skull to ! int]nal e> %\ld be f\nd   
n[1 & a memor&um-sket* made ( ! ducts   
!mselves4  ,,dorsal ,,surface ,,( ,,!   
,,bra94 ,! ro( ( ! skull %\ld be remov$ 
f ov] ! bra94 ,use a %>p scalpel & take 
v ?9 slices ( c>tilage4 ,d n cut beyond 
! bra9 at ! sides4 ,no attempt %\ld be  
made at ?is "t to expose m ?an ! dorsal 
surface ( ! bra94  ,above ! ant]ior end 
( ! bra9 !re is a small m$ian =am5 ?r\gh
 ! skull1 ! epiphysial =am54 ,a /r& (   
tissue1 ! epiphysis1 lead+ f ?is to !   
surface ( ! bra91 %\ld be c>efully      
obs]v$ & reta9$4 ,! c>tilage %\ld also  
be cut away f above ! portion ( ! sp9al 
cord next ! skull4 ,g5tly wa% away any  
coagulat$ lymph4  ,! bra9 & sp9al cord  
are inve/$ by two membranes 7m5+es74 ,! 
t\gh dura mat] l9es ! cavity 9 :i* !y   
lie1 cl++ closely to ! c>tilage2 9 fact 
x =ms ! p]i*ondrium ( ! int]nal surface 
( ! cranium4 ,! pia mat] envelops       

closely ! bra9 & cord1 & conta9s num]\s 
blood vessels4 ,betwe5 ! two is !       
ara*noid space1 trav]s$ by occasional   
f9e ?reads ( connective tissue & fill$ )
 lymph4  ,z ! sp9al cord passes =w>d    
into ! skull x enl>ges & m]ges ) !      
po/]ior portion ( ! bra91 ! m$ulla      
oblongata 7myel5cephalon74 ,! ro( ( !   
m$ulla is extremely ?91 & is brok5 if ! 
c>tilage has n be5 remov$ ) extreme c>e1
 expos+ a cavity )91 ! f\r? v5tricle4   
,9 front ( ! m$ulla1 & ov]lapp+ its     
ant]ior extremity1 is a l>ge oval organ1
 ! c]ebellum 7met5cephalon74 ,v5tral to 
! c]ebellum1 ea* side ( ! m$ulla is     
exp&$ 9 an e>-%ap$ lobe1 ! corpus       
re/i=mis4 ,ant]iorly1 ! c]ebellum       
ov]laps a pair ( r\nd$ lobes1 ! optic   
lobes1 :i* toge!r =m ! dorsal portion ( 
! midbra9 7mes5cephalon74  ,9 front ( ! 
optic lobes are two slightly l>g] lobes 
unit$ 9 _! po/]ior portions b sep>at$   
ant]iorly1 ! c]ebral lobes or           
hemisph]es4 ,toge!r !y con/itute !      
pros5cephalon4 7,! pros5cephalon is n   

divid$ 9 ,eugaleus47 ,betwe5 !          
mes5cephalon & ! pros5cephalon is a     
depress$ region belong+ to ! bra9-/em1 !
 di5cephalon 7?alam5cephalon71 f :i* !  
epiphysis arises4 ,! ro( ( ! di5cephalon
 also is v ?9 & is frequ5tly brok5 dur+ 
! exposure ( ! bra94 ,! cavity se5 )9 ! 
di5cephalon is ! ?ird v5tricle4  ,/alk$ 
bodies aris+ f ! ant]o-lat]al angles ( !
 c]ebral hemisph]es are ! olfactory     
lobes4 ,! portion ( ! bra9 includ+ !    
c]ebral hemisph]es & ! olfactory lobes  
con/itutes ! tel5cephalon4  ,,dissection
 ,,( ,,! ,,int]nal ,,e>4 ,! /ructures   
compos+ ?is organ lie 9 ! project+      
c>tilage at ! side ( ! m$ulla 7auditory 
capsule74 ,remove ! c>tilage ( !        
auditory capsule 9 ?9 slices & bit by   
bit1 foll[+ ! ductus endolymphaticus to 
! membrane\s labyr9?4 ,dissect away !   
surr\nd+ c>tilage leav+ ! membrane\s    
canals 9 place1 until ! entire labyr9?  
is expos$4 ,! membrane\s labyr9? consi/s
 ( a l>ge c5tral sac 7utriculo-saccul>  
*amb]7 into :i* ! endolymphatic duct    

op5s1 & ?ree membrane\s tubes           
7semicircul> canals7 ext]nal to ! *amb] 
b communicat+ ) x 9 v>i\s ways4 ,two1 "o
 ant]ior & ! o!r po/]ior to ! sacculus1 
lie 9 a ne>ly v]tical plane 7ant]ior &  
po/]ior semicircul> canals72 "o is      
ext]nal to ! sacculus & lies 9 a ne>ly  
horizontal plane 7horizontal or ext]nal 
semicircul> canal74 ,at ! v5tral ends ( 
! v]tical canals are ne>ly sph]ical     
enl>gem5ts call$ ampullae4 ,! ampulla ( 
! horizontal canal is at its ant]ior    
end4 ,! dorsal ends ( ! v]tical canals  
op5 ne> ea* o!r into ! upp] "p ( !      
utriculo-sacculus4 ,! v5tral extremity (
 ! ant]ior v]tical canal & ! ant]ior    
extremity ( ! horizontal canal op5      
beside ea* o!r into an ant]ior          
projection ( ! sacculus4 ,! v5tral      
extremity ( ! po/]ior v]tical canal op5s
 into ! po/]ior & l[] "p ( ! sacculus4  
,! po/]ior extremity ( ! horizontal     
canal op5s into ! po/]ior side ( !      
sacculus4 ,dur+ life ! utriculo-sacculus
 & ! semicircul> canals are fill$ ) a   

lymphatic fluid1 & ! sacculus conta9s a 
l>ge calc>e\s e>-/one 7otoli?71 :i* is  
usually dissolv$ by ! =mal9 us$ 9       
pres]v+ ! dogfi%4  ,:iti% pat*es (      
?ick5$ s5sory epi!lium may be se5 9 !   
ampullae 7cri/ate acu/icae7 & 9 !       
utriculo-saccul> *amb] 7maculae         
acu/icae74 ,bran*es ( ! eigh? n]ve c be 
foll[$ to all ^! areas4  ,a projection (
 ! v5tral wall ( ! utriculo-sacculus is 
! lag5a1 ! rudim5t f :i* ! co*lea (     
high] animals develop$4 ,x also conta9s 
a macula acu/ica4  ,,ext]nal ,,features 
,,( ,,! ,,eye4 ,obs]ve ! transp>5t      
cornea cov]+ ! ext]nal surface ( ! eye2 
! d>k r+ ( ! iris2 ! c5tral op5+ 9 !    
iris1 ! pupil2 ! conjunctival sac       
surr\nd+ ! ext]nal half ( ! eyeball4    
,cut away suffici5t ( ! upp] wall ( !   
c>tilag9\s orbit to expose ! eyeball &  
its muscles4 ,note ! consid]able am\nt (
 s(t connective tissue ar\nd ! eye &    
explore ! orbital s9us 7p4 #ac74 ,take  
notice ( ! foll[+ n]ves1 9 ord] to      
ensure _! pres]vation until ! "t comes  

to trace !m m completely4 ,a l>ge n]ve  
cross+ ! m$ial side ( ! orbit1 !        
sup]ficial oph?almic2 a n]ve leav+ !    
cranium opposite ! optic lobe1 pass+ "u 
! sup]ficial oph?almic to ! ant]ior     
muscle ( ! eyeball1 ! tro*le>2 sev]al   
long cili>y n]ves pass+ to ! eyeball2   
sev]al o!r n]ves visible 9 ! deep angle 
( ! orbit4  ,six muscles move ! eye4    
,f\r ( ^! arise close toge!r at ! deep  
po/]o-m$ial angle ( ! orbit4 ,div]g+1 !y
 are ins]t$ ^u f\r sides ( ! eyeball1 & 
f ! position ( _! ins]tions are nam$ !  
sup]ior1 po/]ior1 inf]ior1 & ant]ior    
recti4 ,two muscles arise f !           
ant]o-m$ial angle ( ! orbit1 ! sup]ior &
 inf]ior oblique muscles4  ,betwe5 !    
recti muscles c be se5 a mu%room-%ap$   
/alk ( c>tilage1 ! oph?almic p$uncle2 ! 
eyeball re/s aga9/ its exp&$ end4 7,!re 
is no p$uncle 9 ,eugaleus47  ,,!        
,,cranial ,,n]ves4 ,! cranial n]ves are 
twelve pairs ( n]ves aris+ f ! bra91 &  
?us di/+ui%$ f ! sp9al n]ves :i* arise f
 ! sides ( ! sp9al cord4 ,!y are        

di/ribut$ *iefly to ! head & neck1 ?\gh 
bran*es ( ! vagus n]ve g to ! visc]a &  
to ! s5se organs ( ! lat]al l9e4 ,s9ce !
 n]ves are all pair$1 ! di/ribution (   
bo? n]ves ( a pair be+ alike1 !         
descriptions w m5tion b "o n]ve ( a     
pair4 ,z ! cranial n]ves are trac$      
dissect away ! sides ( ! cranium d[n to 
! =am9a p5etrat$ by ! n]ves1 & foll[ ea*
 n]ve f its orig9 on ! bra9 to ! p>ts   
inn]vat$ by x4 ,features ( ! dissection 
:i* are n f\nd 9 trac+ ! n]ve ( "o side 
%\ld be s\ght on ! o!r side4  ,!        
olfactory n]ve4 ,! ant]ior surface ( !  
olfactory lobe fills a l>ge =am5 9 !    
ant]ior wall ( ! cranium & is press$    
closely aga9/ ! po/]ior surface ( !     
nasal sac4 ,num]\s small n]ves1         
collectively =m+ ! olfactory n]ve1 arise
 f ! ant]ior face ( ! lobe1 p5etrate !  
membrane\s wall ( ! olfactory organ1 &  
are di/ribut$ to its highly fold$       
surface4  ,! t]m9al n]ve1 ,n]vus        
t]m9alis1 is a sl5d] n]ve runn+ along ! 
m$ial surface ( ! /alk ( ! olfactory    

lobe4 ,foll[ x backw>d to its orig9 on !
 ant]ior surface ( ! c]ebral hemisph]e1 
deep 9 ! m$ian fissure 79 ,eugaleus on !
 v5tral surface74 ,trace x =w>d ov] !   
dorsal surface ( ! olfactory lobe to :]e
 x ent]s ! nasal sac4 ,! t]m9al n]ve is 
a true cranial n]ve :i* has escap$      
notice until rec5t ye>s4 ,x is associat$
 ) ! olfactory n]ve 9 v]tebrates g5]ally
 f fi%es to m54 ,! fibres ( ! t]m9al    
n]ve rema9 di/9ct f ^? ( ! olfactory    
n]ve1 bo? 9 ! olfactory organ & 9 !     
bra94 ,its function is unkn[n4 ,!re is  
/ill a division ( op9ion among          
au?orities z to :e!r ! t]m9al n]ve %\ld 
be consid]$ to be a di/9ct cranial n]ve1
 or a portion ( ! olfactory n]ve4  ,!   
optic n]ve c be se5 at ! bottom ( !     
orbit betwe5 ! eye & ! skull1 ne>ly "u !
 sup]ior oblique muscle4 ,x arises f !  
v5tral side ( ! di5cephalon1 passes     
outw>d1 p5etrates ! orbit at its        
inf]o-m$ial angle1 & cont9ues directly  
outw>d to ! eyeball4  ,! tro*le> n]ve1  
or pa!ticus1 p5etrates ! wall ( ! orbit 

opposite ! optic lobe4 ,foll[ x back to 
its orig9 f ! dorsal surface ( ! bra9 9 
! depression betwe5 ! optic lobes & !   
c]ebellum4 ,!n foll[ x f ! skull to !   
sup]ior oblique muscle1 :i* x inn]vates4
  ,! oculo-motor n]ve arises f ! v5tral 
surface ( ! midbra91 passes outw>d1 &   
p5etrates ! orbit on a level ) & j      
ant]ior to ! orig9s ( ! recti muscles4  
,x divides imm$iately into ?ree p>ts2   
two pass to ! ant]ior & sup]ior recti   
respectively1 :ile ! ?ird passes d[nw>d 
along ! po/]ior surface ( ! eyeball to !
 inf]ior rectus & inf]ior oblique       
muscles4 ,9 trac+ ?is n]ve ! palat9e    
process ( ! upp] jaw w be se5 project+ f
 bel[ into ! orbit4  ,! trigem9al1      
facial1 & auditory n]ves spr+ f ! side (
 ! m$ulla bel[ ! corpus re/i=mis4 ,!    
roots1 & "s ( ! bran*es1 ( ! trigem9al &
 facial n]ves are s m+l$ z to be        
indi/+ui%able except by special         
neurological te*nique4 ,! common root ( 
! trigem9al & facial n]ves %[s a p>tial 
division into a dorsal & a v5tral       

portion2 ! dorsal portion belongs to !  
facial n]ve1 :ile ! v5tral root is mix$4
 ,! root ( ! auditory n]ve lies close   
beh9d ! trigem9al-facial root1 b c be   
di/+ui%$ fairly well4 ,bo? ! trigem9al &
 facial n]ves divide into sev]al trunks1
 namely3                      ,trigem9al
      ,facial                           
sup]ficial     sup]ficial               
oph?almic      oph?almic                
deep oph?almic buccal                   
maxill>y       otic                     
m&ibul>      hyom&ibul>  ,! sup]ficial  
oph?almic trunks ( ! two unite 9 a s+le 
n]ve :i* passes along ! inn] wall ( !   
orbit above ! muscles ( ! eye to a =am5 
9 ! ant]o-m$ial angle ( ! orbit1 ?r\gh  
:i* x passes to ! dorsal surface ( !    
sn\t4 ,! sup]ficial oph?almic n]ve (    
,squalus is compos$ almo/ entirely (    
fibres ( ! facial n]ve4 ,! sup]ficial   
oph?almic trunk ( ! trigem9al gives rise
 to sev]al small n]ves leav+ ! common   
trunk ne> its orig9 & pass+ to ! sk9    
above ! eye4 ,! sup]ficial oph?almic    

trunk ( ! facial1 ne>ly ! :ole ( !      
common n]ve1 bran*es pr(usely to supply 
! s5sory organs ( ! dorsal & lat]al     
surfaces ( ! sn\t4  ,! sup]ficial       
oph?almic ( ,eugaleus rises f ! dorsal  
"p ( ! trigem9o-facial root & leaves !  
cranium by a sep>ate =am5 above &       
ant]ior to ! roots ( ! recti muscles4   
,directly "u ! orig9 ( ! sup]ficial     
oph?almic w be f\nd a comp>atively sl5d]
 n]ve1 :i* passes betwe5 ! sup]ior &    
po/]ior rectus muscles1 & =w>d along !  
m$ial surface ( ! eyeball2 x p5etrates !
 ant]ior wall ( ! orbit by a sep>ate    
=am51 & em]ges "u ! sup]ficial          
oph?almic4 ,x is di/ribut$ to ! sk9 ( ! 
dorsal & lat]al surfaces ( ! sn\t4 ,?is 
is ! deep oph?almic 7oph?almicus        
pr(undus7 ( ! trigem9al n]ve4 ,a sl5d]  
bran* 7po/]ior cili>y n]ve7 passes f !  
deep oph?almic ne> its orig9 to !       
po/]ior surface ( ! eyeball4 ,f>!r =w>d 
! same trunk gives (f an ant]ior cili>y 
n]ve to ! ant]ior "p ( ! eyeball4  ,a   
l>ge n]ve :i* crosses ! floor ( ! orbit1

 b5ea? ! eyeball1 consi/s ( ! maxill>y  
trunk ( ! trigem9al & ! buccal trunk ( !
 facial n]ve4 ,^! rema9 associat$1 ev5  
into ! small bran*es4 ,ne> ! ant]ior    
m>g9 ( ! orbit ! maxill>y-buccal trunk  
divides into ?ree p>ts2 ! smalle/ & out]
 "o passes to ! surface lat]al & ant]ior
 to ! eye4 ,! o!r two dip d[nw>d & pass 
9 front ( ! jaw to ! v5tral surface ( ! 
sn\t4 ,reflect ! sk9 ( ! v5tral surface 
( ! sn\t1 & by dissection expose ^!     
n]ves z !y em]ge f ! orbit4 ,! l>g]     
bran* runs =w>d close to ! m$ian l9e ( !
 sn\t1 giv+ (f num]\s twigs2 ! o!r1 :i* 
appe>s to be a pure trigem9al bran*1 is 
di/ribut$ ne> ! angle ( ! m\?4 ,! fibres
 ( ! maxill>y trunk supply ! sk91 :ile  
^? ( ! buccal g to ! canal organs &     
ampullae ( ,lor5z9i4  ,! m&ibul> trunk (
 ! trigem9al n]ve arises b5ea? & beh9d !
 maxill>y4 ,x passes outw>d 9 front ( ! 
levator maxillae sup]ioris muscle1 s5d+ 
a few twigs into ?is muscle1 & turns    
d[nw>d ov] ! palato-quadrate c>tilage4  
,x divides "h1 "o "p ent]+ ! adductor   

m&ibul>is muscle1 ! o!r pass+ d[nw>d    
along ! edge ( ! m&ible1 inn]vat+ ! sk9 
( ! l[] jaw & ! fir/ v5tral sup]ficial  
con/rictor muscle4  ,! m&ibul> &        
maxill>y-buccal trunks ( ,eugaleus are  
unit$ until !y approa* ! edge ( ! orbit1
 & ! palat9e bran* is mu* l>g]2 o!rwise 
! trigem9o-facial bran*es are mu* z 9   
,squalus4  ,! hyom&ibul> trunk ( !      
facial n]ve c be f\nd j b5ea? ! sk9     
beh9d & close to ! spiracle4 ,f "h x c  
be foll[$ back to ! bra94 ,x arises f ! 
v5tral "p ( ! trigem9o-facial root1     
em]g+ f ! cranium ?r\gh ! hyom&ibul>    
canal4 ,x divides into a numb] ( bran*es
 j beyond ! spiracle3  #a4 ,! ext]nal   
m&ibul> bran* consi/s ( two portions1 a 
small ant]ior n]ve ext5d+ ant]o-v5trally
 to ! canals above & bel[ ! angle ( !   
m\?1 & a l>g] n]ve :i* passes lat]ally &
 sudd5ly breaks up into a bru% ( twigs  
:i* inn]vate ! hyoidean gr\p ( ampullae4
  #b4 ,! int]nal m&ibul> bran* arises at
 ab\t ! same level z ! ext]nal m&ibul>1 
b "u x1 passes inw>d ar\nd ! edge ( !   

hyoid c>tilage1 "u ! adductor m&ibul>is 
muscle1 & !n =w>d along ! m&ibul>       
c>tilage4  #c4 ,! hyoid bran* sep>ates f
 ! hyom&ibul> trunk at ab\t ! same level
 z ! prec$+ n]ves1 & !n passes1 deep 9 !
 tissues1 ar\nd ! angle ( ! jaw to !    
v5tral side :]e x is di/ribut$ to !     
sup]ficial con/rictor muscles4 ,sev]al  
n]ves pass f ! hyom&ibul> trunk & !     
hyoid bran* to ! dorsal sup]ficial      
con/rictors4  #d4 ,! palat9e bran* spr+s
 f ! base ( ! hyom&ibul> trunk inside ! 
hyom&ibul> canal4 ,x passes outw>d &    
=w>d1 divid+ into num]\s bran*es :i*    
inn]vate ! muc\s membranes ( ! m\?4 ,x c
 be trac$ completely lat]4  ,"o or m    
small n]ves proce$+ to ! pseudobran* &  
ant]ior wall ( ! spiracle arise ne> !   
po9t ( orig9 ( ! palat9e bran*4  ,! otic
 n]ve1 pass+ f ! root ( ! facial n]ve to
 ! po/orbital canal1 is n likely to be  
f\nd 9 ?is dissection4  ,obs]ve !       
enl>gem5t ne> ! base ( ! hyom&ibul>     
trunk1 & )9 ! c>tilag9\s canal1 !       
g5iculate ganglion4 ,! gass]ian         

ganglion1 a compon5t ( ! trigem9al n]ve1
 lies 9 ! v5tral portion ( !            
trigem9al-facial root1 & c n[ be locat$4
  ,! auditory n]ve arises close beh9d ! 
v5tral division ( ! trigem9o-facial     
root4 ,! root ( ! auditory n]ve encloses
 a l>ge auditory ganglion4 ,a ve/ibul>  
n]ve arises f ! ant]ior end ( ! auditory
 ganglion & passes into ! e> capsule1   
inn]vat+ ! upp] "p ( ! utriculo-sacculus
 & ! ampullae ( ! ant]ior & horizontal  
canals4 ,f ! po/]ior "p ( ! ganglion    
n]ves pass to ! v5tral "p ( ! sacculus &
 ! ampulla ( ! po/]ior canal4 ,trace ^! 
bran*es z ?or\ghly z possible4  ,!      
abduc5s n]ve em]ges f ! cranium "u &    
close to ! orig9 ( ! po/]ior rectus     
muscle1 into :i* muscle x ent]s4 ,to    
expose ?is n]ve ! trigem9al1 facial &   
auditory n]ves mu/ be lift$ & cut z !y  
pass ?r\gh ! wall ( ! cranium4 ,x c be  
trac$ obliquely backw>d & inw>d1 ?r\gh a
 long canal1 to its orig9 ne> ! midl9e (
 ! v5tral surface ( ! m$ulla4  ,!       
glossoph>yngeal n]ve passes ?r\gh ! base

 ( ! e> capsule f ! side ( ! m$ulla to !
 upp] end ( ! fir/ bran*ial p\*4 ,a     
ganglionic enl>gem5t is f\nd ne> :]e x  
em]ges f ! c>tilage4 ,outside ! cranium 
! glossoph>yngeal divides into a        
pretrematic bran*1 pass+ d[n 9 front ( !
 fir/ gill p\*1 & a po/trematic bran*   
runn+ beh9d ! p\*4 ,! pretrematic bran* 
quickly s5ds (f a ph>yngeal n]ve :i*    
runs ant]o-v5trally to ! ro( ( ! ph>ynx4
 ,! pretrematic & po/trematic bran*es c 
be foll[$ along ! gill ar* to ! v5tral  
side ( ! ph>ynx4 ,a f\r? bran* ( !      
glossoph>yngeal1 ! supratemporal1 spr+s 
f ! dorsal side ( ! ganglion2 pass+     
?r\gh ! e> capsule x runs to ! dorsal   
surface ( ! head1 :]e x is di/ribut$ to 
! s5se organs ( a %ort section ( !      
lat]al l9e canal4 ,?is small n]ve c be  
demon/rat$ by c>efully sep>at+ ! muscles
 & p]i*ondrium f ! po/]ior surface ( !  
auditory capsule4  ,! vagus n]ve 7or    
pneumoga/ric7 arises by an ext5sive     
s]ies ( roots f ! side ( ! m$ulla4 ,an  
easily di/+ui%$ ribbon-l portion ( !    

root1 ! lat]al l9e root1 runs =w>d z f> 
z ! root ( ! glossoph>yngeal4 ,note !   
canal by :i* ! vagus leaves ! cranium1 &
 trace ! n]ve along ! inn] side ( !     
ant]ior c>d9al ve94  ,! pr9cipal bran*es
 ( ! vagus are3  #a4 ,! supratemporal   
bran*1 a small n]ve runn+ dorsal ?r\gh !
 po/]ior "p ( ! e> capsule to ! lat]al  
l9e canal & o!r s5se organs ( ! head4 ,x
 w be f\nd ne> ! supratemporal bran* ( !
 glossoph>yngeal4  #b4 ,! lat]al l9e    
bran*1 a l>ge n]ve :i* sep>ates f !     
trunk ( ! vagus j outside ! cranium &   
runs backw>d ?r\gh ! muscles1 p>allel to
 ! v]tebral column on a level ) ! lat]al
 l9e4 ,x s5ds (f num]\s small twigs to !
 s5se organs ( ! lat]al l9e canal4  #c4 
,f\r bran*ial n]ves1 :i* c be se5 ?r\gh 
! floor ( ! ant]ior c>d9al ve91 leave ! 
out] side ( ! vagus trunk4 ,ea* divides 
into a pretrematic & po/trematic bran*2 
a ph>yngeal bran*1 ! la/ ( :i* is !     
l>ge/1 arises f ea* po/trematic4  #d4   
,beyond ! bran*ial n]ves ! rema9d] ( !  
vagus passes backw>d z ! inte/9al or    

visc]al trunk1 to ! end ( ! ph>ynx1 :]e 
x divides into a numb] ( bran*es :i* are
 di/ribut$ *iefly to ! wall ( ! /oma*4  
,ne> ! po9t ( ?is la/ division ! vagus  
is cross$ by ! hypobran*ial n]ve1 :i*   
%\ld be not$ & pres]v$4  ,! occipital   
n]ve p5etrates ! lat]al wall ( ! cranium
 close beh9d ! root ( ! vagus & ent]s ! 
canal ( ! vagus1 along :i* x passes4 ,on
 em]g+1 x s5ds small bran*es to ! ne>by 
muscle1 :ile ! pr9cipal portion runs on 
to jo9 ! hypobran*ial n]ve4 ,! occipital
 n]ve w be f\nd to arise f ! v5tral     
surface ( ! m$ulla1 bel[ & beh9d ! root 
( ! vagus1 by two or m di/9ctly sep>at$ 
roots1 :i* may repres5t di/9ct n]ves4   
,,sp9al ,,n]ves4 ,! sp9al n]ves are ^?  
n]ves :i* arise f ! sides ( ! sp9al     
cord4 ,!y diff] f ! cranial n]ves n only
 9 _! orig9 outside ! cranium1 b also 9 
t ea* sp9al n]ve arises by two roots :i*
 spr+ f ! sp9al cord ne> ! dorsal &     
v5tral surfaces4 ,ea* root passes ?r\gh 
a =am5 9 ! c>tilag9\s wall ( ! neural   
canal1 ! v5tral a little ant]ior to !   

dorsal1 aft] :i* !y unite to =m ! sp9al 
n]ve4 ,betwe5 ! junction ( ! roots & its
 =am5 ! dorsal root conta9s a mass (    
ganglion cells1 :i* cause an enl>gem5t  
kn[n z ! dorsal root ganglion4 ,!       
typical c\rse ( a sp9al n]ve is ar\nd ! 
body to ! v5tral surface1 giv+ (f       
bran*es to ! muscles & sk9 ( its segm5t4
 ,a %ort di/ance f ! v]tebral column !  
sp9al n]ves lie j outside ! p]itoneum1  
?r\gh :i* _m ( !m c be se5 & foll[$ to  
ab\t ! level ( ! lat]al ve94 ,at ?is    
po9t !y pass outw>d into ! muscles ( !  
body wall4 ,to dissect any ( ! sp9al    
n]ves make a longitud9al incision along 
! lat]al l9e & sep>ate ! dorsal muscle  
mass f ! lat]al muscles = "s di/ance4 ,!
 dorsal muscles c !n be press$ t[>d !   
v]tebral column & dissect$ away f !     
p]itoneum4 ,! sp9al n]ves1 ly+ aga9/ !  
p]itoneum1 w be expos$ & c be foll[$    
easily1 fir/ to _! roots1 next v5trally4
  ,! hypobran*ial n]ve1 to :i* att5tion 
0 call$ at ! po9t :]e x crosses ! vagus1
 is =m$ by ! union ( ! pr9cipal bran*es 

( ! occipital & fir/ two sp9al n]ves4 ,!
 ?ird sp9al n]ve receives a bran* f !   
second1 & itself accompanies !          
hypobran*ial n]ve closely )\t actually  
becom+ a "p ( x4 ,! union ( n]ves ?us   
=m$ is kn[n z a plexus4 ,aft] cross+ !  
vagus ! hypobran*ial n]ve =ks1 "o       
division pass+ m$ial to1 ! o!r lat]al to
 ! ant]ior c>d9al ve92 bo? run v5trally1
 foll[+ ! la/ gill ar*1 & reunite on !  
lat]al wall ( ! p]ic>dium1 =m+ a trunk  
:i* runs =w>d4 ,at ! ant]ior end ( !    
p]ic>dium ?is divides into a dorsal & a 
v5tral bran* :i* inn]vate ! surr\nd+    
muscles4 ,! hypobran*ial n]ve inn]vates 
! sk9 ( ! region imm$iately 9 front ( ! 
pectoral girdle1 & ! coraco-arcualis    
communis1 coraco-m&ibul>is1             
coracohyoideus1 & coraco-bran*ialis     
muscles4  ,! ?ird1 f\r?1 fif? & six?    
sp9al n]ves pass backw>d & v5trad till  
!y rea* ! level ( ! articulation ( !    
pectoral f9 ) ! girdle4 ,"h !y jo9 to =m
 a simple bra*ial plexus1 f :i* arise   
bran*es proce$+ to ! musculature ( !    

dorsal & v5tral faces ( ! f94 ,! sev5?  
to elev5? sp9al n]ves pass d[nw>d to !  
level ( ! f91 & !n bran*1 "o portion    
ent]+ ! muscles ( ! v5tral body wall1   
:ile ! o!r passes into ! depressor      
muscles ( ! f94  ,! pelvic f9 is        
inn]vat$ by eight or n9e sp9al n]ves :i*
 pass backw>d & d[nw>d along ! m$ial    
edge ( ! septum betwe5 ! myom]es1 ent]+ 
! dorsal side ( ! f9 along its axis4 ,no
 plexus is =m$4  ,,olfactory ,,organ    
7,,nasal ,,sac74 ,dissect away ! sk9 &  
o!r tissues ar\nd ! no/ril s z to expose
 completely ! olfactory organ2 ?is w be 
f\nd to be a d>k-color$1 ne>ly sph]ical 
mass1 ( half ! diamet] ( ! eye1 firmly  
atta*$ at its base4 ,by cutt+ away !    
c>tilage dorsal to ! nasal sac its base 
w be expos$1 & ! olfactory bulb w be %[n
 to be closely adh]5t to a consid]able  
"p ( ! po/]o-dorsal surface ( ! organ4  
,num]\s %ort n]ves c be demon/rat$ to   
pass f ! olfactory bulb into ! olfactory
 organ2 all ^! n]ves toge!r are consid]$
 z ! fir/ cranial or olfactory n]ve4    

,remove ! olfactory organ f ! head2     
divide x by a m$ian longitud9al cut2    
obs]ve ! arrangem5t & /ructure ( its    
d\ble s]ies ( int]nal folds 7lamellae71 
& ! complete m$ian septum4  ,,v5tral    
,,surface ,,( ,,! ,,bra94 ,cut ! cord 9 
two "s di/ance back ( ! bra94 ,cut all  
cranial n]ves j inside ! cranium &      
c>efully lift ! bra9 out4 ,p>ts ( !     
v5tral portion ( ! bra9 lie 9 a recess  
b5ea? ! mes5cephalon & mu/ be dis5gag$ v
 g5tly4  ,id5tify & exam9e ! v5tral p>ts
 ( ! bra94 ,note ! consid]able lat]al   
compression ( ! mes5cephalon4 ,! optic  
n]ves cross b5ea? ! di5cephalon1 =m+ !  
optic *iasma4 ,f ! sides ( ! *iasma     
slightly elevat$ optic tracts1 =m$ by ! 
fibres ( ! optic n]ves1 c be trac$ into 
! optic lobes4  ,back ( ! optic *iasma !
 project+ v5tral portion ( ! di5cephalon
 =ms ! hypo?alamus4 ,! po/]ior lobe (   
?is /ructure is ! hypophysis or pituit>y
 body4  ,! oculo-motor n]ves em]ge ov] !
 po/]ior end ( ! hypo?alamus4  ,! v5tral
 portion ( ! mes5cephalon is =m$ by !   

c]ebral p$uncles 7crura c]ebri71 columns
 ( fibres pass+ betwe5 ! myel5cephalon &
 tel5cephalon4  ,! abduc5s n]ves arise  
on ! v5tral surface ( ! myel5cephalon   
ne> ! midl9e & j back ( a l9e connect+ !
 roots ( ! auditory n]ves4  ,! int]nal  
c>otid art]ies rea* ! bra9 at ! sides ( 
! hypo?alamus4 ,bran*es are s5t upw>d & 
=w>d ov] ! surface ( ! bra94 ,ana/omoses
 betwe5 ! vessels ( ! opposite sides are
 =m$ ant]ior to ! optic *iasma4 ,! ma9  
bran*es ( ! c>otids pass backw>d along !
 sides ( ! hypo?alamus & unite beh9d ?is
 organ4 ,! m$ian art]y ?us =m$ runs     
along ! v5tral surface ( ! myel5cephalon
 & ! sp9al cord4 ,num]\s transv]se      
vessels are giv5 (f to ! myel5cephalon4 
,id5tify ! roots ( ! rema9+ cranial     
n]ves4  ,,cavities ,,( ,,! ,,bra94      
,divide ! bra9 into exactly equal halves
 by a v]tical longitud9al cut4  ,ea*    
lobe ( ! pros5cephalon conta9s a l>ge   
cavity4 ,^! are ! prosocoels4 ,!y are   
commonly kn[n ei!r z ! lat]al v5tricles1
 or ! left cavity z ! fir/ v5tricle & ! 

"r z ! second v5tricle4 ,! prosocoels   
are cont9u$ into ! olfactory lobes1 ^!  
portions be+ kn[n z rh9ocoels4  ,!      
?alamocoel is ! cavity )9 ! di5cephalon1
 (t5 call$ ! ?ird v5tricle4 ,!          
prosocoels communicate ) ! ?alamocoel by
 lat]al op5+s1 ! =am9a ( ,monro4 ,! ro( 
( ! ?alamocoel is v ?9 & is non-n]v\s2 x
 is frequ5tly torn dur+ ! e>ly          
dissection4 ,:]e ! lobes ( !            
pros5cephalon meet ! dorsal wall ( !    
di5cephalon ?is ?9 ro( is pu%$ into !   
prosocoels1 c>ry+ ) x ! pia mat] & its  
blood vessels1 & ?us =ms vascul> +r[?s  
kn[n z ! *oroid plexi4 ,! ?alamocoel    
cont9ues above into ! epiphysis & bel[  
into ! hypo?alamus4  ,! myelocoel is !  
l>ge cavity ( ! myel5cephalon4 ,x also  
is frequ5tly app>5tly op5 to ! ext]ior  
at ! po/]ior end by ! accid5tal break+ (
 ! ?91 non-n]v\s dorsal wall ( ?is      
region4 ,! myelocoel is also kn[n z !   
f\r? v5tricle4  ,! ?alamocoel &         
myelocoel are connect$ by a n>r[ passage
 ?r\gh ! mes5cephalon1 ! aqu$uct (      

,sylvius 7it]1 mesocoel74  ,! optocoels 
are l>ge cavities )9 ! optic lobes :i*  
op5 into ! aqu$uct ( ,sylvius4  ,a l>ge 
metacoel 9 ! met5cephalon op5s into !   
myelocoel4 ,! myelocoel is also cont9u$ 
into ! corpora re/i=ma2 po/]iorly x jo9s
 ! c5tral canal :i* ext5ds d[n ! c5t] ( 
! sp9al cord4  ,,dissection ,,( ,,!     
,,eye4 ,remove "o ( ! eyes f its orbit1 
& divide x into inn] & out] halves by an
 equatorial cut ar\nd ! eyeball 7n      
directly ?r\gh x1 z ?is te>s ! l5s f its
 fa/5+s74 ,place ! halves "u wat] &     
obs]ve3  ,9 ! inn] half3  ,! po/]ior    
*amb]1 ! cavity ( ! eyeball :i* has be5 
op5$4 ,dur+ life x is fill$ by a        
gelat9\s sub/ance1 ! vitre\s humor4  ,! 
ret9a1 a delicate yell[i%-:ite membrane 
l9+ ! int]ior ( ! eye1 loosely atta*$ to
 ! out] coats except at ! po9t (        
entrance ( ! optic n]ve4  ,! *oroid     
coat1 a ?91 black membrane outside !    
ret9a4 ,x c be pull$ away f ! out] coat 
q easily except ne> ! optic n]ve4  ,!   
scl]otic coat1 ! out] coat ( ! eye4 ,?is

 is compos$ ( connective tissue hav+ an 
almo/ c>tilag9\s consi/5cy1 is only     
slightly pigm5t$1 & is some:at          
transluc5t4 ,! muscles ( ! eye are      
ins]t$ ^u ! scl]otic4  ,9 ! out] half3  
,! ora s]rata1 an irregul> l9e along :i*
 ! ret9a ends4  ,! iris1 a fold ( !     
*oroid ext5d+ inw>d l a %elf1 & p]=at$  
c5trally to =m ! pupil4 ,ar\nd ! iris ! 
*oroid is fold$ radially into ! cili>y  
processes4  ,! l5s1 a sph]ical body1    
transp>5t & ela/ic dur+ life1 b opaque &
 h>d 9 pres]v$ specim5s4 ,x projects    
into ! pupil & is susp5d$ f ! cili>y    
processes by a delicate membrane1 !     
susp5sory ligam5t4  ,! ant]ior *amb]1 9 
front ( ! iris & l5s1 fill$ ) a wat]y   
fluid1 ! aque\s humor4  ,! transp>5t    
cornea1 =m+ ! out] side ( ! eyeball1    
cont9u\s ) ! scl]otic4  ,take out ! o!r 
eye & cut x 9 two by a section ?r\gh !  
pupil & optic n]ve4 ,review ! relation (
 ! p>ts4                                
,,! ,,skeleton  ,!re seems to be no easy
 way ( clean+ ! skeleton ( dogfi% :i* h 

be5 pres]v$ 9 =mal9 or alcohol1 ! only  
proc$ure be+ to cut1 pick1 & scrape !   
fle% away f ! skeleton4 ,"t & pati5ce   
are requir$1 b if ^! are all[$ !re is no
 reason :y all ! p>ts ( ! skeleton _c be
 ?or\ghly /udi$4 ,specim5s :i* h be5    
pres]v$ 9 br9e are m easily skeletoniz$4
  ,! skeleton is entirely compos$ (     
c>tilage :i*1 9 l>ge species (          
elasmobran*s & 9 old individuals ( small
 species1 becomes impregnat$ ) lime     
salts1 9 "s cases to su* an ext5t z to  
resemble s(t bone4  ,! p>ts ( ! skeleton
 are frequ5tly gr\p$ "u two heads3 !    
axial skeleton1 compris+ ! skull &      
v]tebral column2 & ! app5dicul>         
skeleton1 includ+ ! pectoral & pelvic   
girdles & ! skeleton ( ! f9s4           
,,v]tebral ,,column4 ,! v]tebral column 
is divid$ into two regions1 ?oracic &   
caudal1 di/+ui%$ by ! slightly diff]5t  
"* ( ! v]tebrae4 ,remove ! muscle &     
connective tissue f ! v]tebral column = 
a %ort di/ance ant]ior to ! fir/ dorsal 
f94 ,c>e is requir$ n to cut away small 

c>tilages occupy+ ! positions ( ribs4   
,n[ remove f ! body ab\t two in*es ( !  
portion ( ! column expos$ ) any         
c>tilag9\s p>ts :i* may be atta*$ to !  
v]tebrae4 ,! v]tical column is made up (
 segm5ts1 call$ v]tebrae4 ,ea* v]tebra  
consi/s ( a l>ge v5tral mass1 ! c5trum1 
& an ar*1 ! neural ar*1 ro(+ ov] !      
dorsal surface ( ! c5trum2 ! ar* is     
compos$ ( sev]al small plates (         
c>tilage4 ,! op5+ enclos$ by ea* c5trum 
& its neutral ar* is ! v]tebral =am52 ! 
jo9$ v]tebral =am9a =m ! neural canal1  
:i* is occupi$ by ! sp9al cord4         
,sep>ate "o ( ! v]tebrae f ! re/4 ,!    
c5trum is deeply concave at ea* end2 su*
 a c5trum is t]m$ amphicoel\s4 ,at !    
middle ( ! c5trum ! concavities meet &  
?us a canal is =m$ ?r\gh x4 ,?is canal &
 ! spaces betwe5 ! ends ( adjo9+        
v]tebrae are fill$ by ! rema9s ( !      
noto*ord1 a r pulpy /ructure ext5d+ f   
end to end ( ! v]tebral column4  ,!     
concave faces ( ! v]tebrae consi/ ( mu* 
firm] c>tilage ?an ! rema9+ portions1   

sometimes ev5 calcifi$4 ,make a         
transv]se section ?r\gh ! middle ( a    
c5trum & obs]ve ! relations ( ! p>ts4   
,on ea* side ( ! c5trum1 ne> ! v5tral   
edge1 is a plate-l projection1 !        
transv]se process4 ,atta*$ to !         
extremity ( ?is is a sl5d] c>tilag9\s   
rib4  ,ea* neural ar* is made up ( two  
di/+ui%able sets ( plates4 ,! fir/      
consi/s ( a pair ( broad neural plates  
ext5d+ upw>d f ea* side ( ! c5trum &    
unit+ ) ea* o!r dorsally4 ,betwe5 !     
neural plates ( two successive v]tebrae 
is a pair 7"o on ea* side7 ( int]cal>y  
plates :i* also unite ov] ! neural      
canal4 ,! int]cal>y plates are ov] !    
jo9t betwe5 ! c5tra4 ,neural & int]cal>y
 plates toge!r make ! lat]al & dorsal   
walls ( ! neural canal4 ,! relations (  
^! plates c sometimes be se5 be/ :5 !   
neural ar* is clean$1 !n cut away f !   
c5trum1 & look$ ?r\gh t[>d ! light4  ,9 
! l[] "p ( ea* neural plate is a small  
=am5 :i* all[s ! passage ( ! v5tral root
 ( ! sp9al n]ve4 ,a =am5 = ! dorsal root

 is f\nd at ab\t ! middle ( ! int]cal>y 
plate4  ,clean & remove "s ( ! caudal   
v]tebrae f ! region j back ( ! cloaca4  
,9 g5]al !y h ne>ly ! same /ructure &   
relations z ! ?oracic v]tebrae1 b h no  
transv]se processes & ! plates ( !      
neural ar*es are n s di/9ct4 ,!re is    
also add$ a v5tral ar* simil> 9 =m to ! 
neural ar*4 ,?is is ! haemal ar*1 9 :i* 
lie ! caudal aorta & ve94 ,its ro( is ! 
surface ( ! c5trum1 ! sides are =m$ by  
pairs ( plates :i* correspond 9 numb] to
 ! c5tra1 & unite ) ea* o!r v5trally4   
,betwe5 ! successive plates are op5+s = 
! passage ( bran*es ( ! art]y & ve94  ,9
 ?is region =am9a = ! roots ( ! sp9al   
n]ves are f\nd only 9 e o!r pair (      
neural & int]cal>y plates4 ,t[>d ! tip (
 ! v]tebral column ! relation ( ! neural
 & int]cal>y plates to ! c5tra becomes v
 irregul>4  ,9 ,eugaleus ! ro( ( !      
neural ar* is =m$ by a r[ ( small1      
diamond-%ap$ plates :i* fit 9 betwe5 !  
o!r two sets4 ,z ^! plates correspond   
morphologically to ! neural sp9es (     

high] v]tebrates1 !y may receive t "n   
"h4 ,x is probable t ! dorsal portion ( 
! ar* 9 ,squalus is compos$ ( simil>    
neural sp9e elem5ts :i* h become fus$ ) 
! neural & int]cal>y plates ( ea* side4 
,,skull4 ,! skull is entirely           
c>tilag9\s1 & comprises ?ree pr9cipal   
divisions3 7#a7 ! cranium1 an undivid$  
mass ( c>tilage lodg+ ! bra9 & ! organs 
( smell1 sight1 & he>+2 7#b7 ! jaws2    
7#c7 ! visc]al ar*es1 or skeletons ( !  
gill ar*es4  7#a7 ,! cranium4 ,a blunt  
prolongation ( ! ant]ior extremity ( !  
cranium =ms ! ro/rum1 :i* supports ! s(t
 tissues ( ! sn\t4 ,at ea* side ( ! base
 ( ! ro/rum ! cranium wid5s abruptly4   
,on ! ant]ior face ( ! wid5$ portion &  
bel[ ! po/]ior angles ( ! ro/rum is a   
pair ( protrud+ olfactory capsules1 9   
:i* ! olfactory sacs are enclos$4 ,an   
oval ap]ture 9 ! po/]ior wall ( ea*     
capsule op5s into ! bra9case & p]mits ! 
passage ( ! olfactory n]ve ?r\gh !      
cranium4  ,back ( ! olfactory capsules  
are l>ge lat]al cavities1 ! orbits4 ,!  

dorsal edge ( ! orbit makes an ov]hang+ 
l$ge1 kn[n z ! supra-orbital cre/4 ,!   
project+ ant]ior & po/]ior angles ( !   
orbit are di/+ui%$ z ! prae- &          
po/orbital processes4  ,! portions ( !  
cranium back ( ! orbit & at ! sides ( ! 
bra9case =m l>ge lat]al projections     
7auditory capsules7 conta9+ ! organs (  
he>+4  ,at ! c5t] ( ! ne>ly v]tical     
po/]ior surface ( ! cranium is a l>ge   
op5+1 ! =am5 magnum1 ?r\gh :i* ! sp9al  
cord passes4  ,at ei!r side ( & bel[ !  
=am5 magnum is a smoo? articulatory     
surface 7occipital condyle7 articulat+ )
 ! c5trum ( ! fir/ v]tebra4  ,! flatt5$ 
v5tral surface ( ! po/]ior "p ( !       
cranium =ms ! ro( ( ! m\?1 or palate4   
,9 ! mid-dorsal l9e ( ! cranium1 betwe5 
! prae-orbital processes1 is a small    
ap]ture op5+ into ! bra9 cavity1 !      
epiphysial =am54 ,x is clos$ dur+ life  
by a t\gh1 fibr\s membrane4 ,! /alk ( ! 
epiphysis ext5ds to ! "u surface ( ?is  
membrane4  ,betwe5 ! auditory capsules  
is a deep depression 9 ! ro( ( ! cranium

 9 ! floor ( :i* c be se5 ! two small   
pores ?r\gh :i* ! ducti endolymphatici  
pass into ! capsules4 ,close beh9d !m   
are two l>g] op5+s = ! p]ilymph ducts4  
,a pair ( =am9a passes ?r\gh ! inn] edge
 ( ! prae-orbital process2 ^! p]mit !   
passage ( ! oph?almic bran*es ( !       
trigem9al & facial n]ves to ! dorsal    
surface ( ! sn\t4 ,ne> ! bottom ( ! inn]
 wall ( ! orbit is ! =am5 ( ! optic     
n]ve4 ,9 ! po/]o-v5tral angle ( ! orbit 
is ! l>ge trigem9o-facial =am5 = ! exit 
( bran*es ( ! trigem9al & facial n]ves2 
9 front ( x is ! small oculo-motor =am54
 ,! extremely small =am5 ( ! tro*le>    
n]ve is almo/ directly above ! optic    
=am51 ne> ! top ( ! inn] wall ( ! orbit4
 ,close bel[ ! trigem9o-facial =am5 is !
 small passage = ! abduc5s n]ve4 ,bel[ !
 abduc5s =am5 is ! transbasal canal4    
,beh9d & bel[ ! trigem9o-facial =am5 are
 two =am9a1 ?r\gh :i* pass ! hyom&ibul> 
bran*es ( ! facial n]ve4 ,! =am5 ( !    
vagus n]ve is close to ! =am5 magnum1 ^u
 ! po/]ior surface ( ! cranium4 ,! =am5 

( ! glossoph>yngeal n]ve is lat]al to t 
( ! vagus1 ne> ! po/]o-lat]al angle ( ! 
cranium4  ,! cranium ( ,eugaleus is mu* 
l t ( ,squalus1 except t ! ro/rum is =m$
 by ?ree rods1 two dorsal & "o v5tral1  
:i* arise f ! front ( ! bra9case &      
conv]ge ant]iorally until !y meet &     
fuse4 ,! olfactory capsules are mu* l>g]
 & ( heavi] c>tilage ?an 9 ,squalus4 ,! 
auditory region simil>ly is m prom95t4  
7#b7 ,! jaws4 ,! jaws 9 reality are !   
fir/ pair ( visc]al or gill ar*es1 & 9  
spite ( ! modification :i* has tak5     
place ?is relation c be se5 easily 9 !  
adult %>k4 ,! upp] jaw consi/s ( a pair 
( palato-quadrate c>tilages1 unit$      
m$ially by ligam5t1 & be>+ ! upp] s]ies 
( tee?4 ,a l>ge hook$ palat9e process   
ext5ds f ea* palato-quadrate c>tilage   
upw>d along ! inn] wall ( ! orbit4 ,!   
l[] jaw likewise consi/s ( a pair (     
,meckel's c>tilages1 unit$ m$ially 7!   
union is call$ ! symphysis71 & be>+ !   
l[] s]ies ( tee?4 ,a pair ( small labial
 c>tilages1 :i* support ! edges ( !     

labial pockets1 lie at ea* corn] ( !    
m\?4  7#c7 ,visc]al ar*es4 ,! fir/ ( !  
visc]al ar*es is mu* l>g] & heavi] ?an !
 re/4 ,x is kn[n z ! hyoid ar*4 ,ea*    
side ( ! ar* consi/s ( two rods (       
c>tilage3 7#a7 ! hyom&ibul> c>tilage1   
:i* articulates ) a di/9ct facet on !   
lat]al surface ( ! auditory capsule1 &  
ext5ds f "h d[nw>d1 outw>d1 & backw>d2  
7#b7 ! c]atohyal c>tilage1 :i* is       
movably articulat$ to ! hyom&ibul> &    
ext5ds d[nw>d1 =w>d & inw>d4 ,! v5tral  
ends ( ! c]atohyals are unit$ by a      
m$ian1 plate-l basihyal4  ,!            
palato-quadrate & ,meckelian c>tilages  
are susp5d$ f ! hyom&ibul> by sev]al    
/rong ligam5ts1 ! direct atta*m5ts ( !  
jaws to ! cranium be+ ( s(t connective  
tissue only4 ,bo? ! hyom&ibul> &        
c]atohyal c>tilages be> sl5d] rods      
7bran*ial rays7 on _! po/]ior edges1 :i*
 support ! ant]ior wall ( ! fir/ gill   
p\*4 ,note ! position ( ! spiracle      
betwe5 ! m&ibul> & hyoid ar*es4 ,!      
ant]ior wall ( ! spiracle is /r5g!n$ by 

two small1 flat1 v]tical c>tilages1     
probably homolog\s ) ! bran*ial rays ( !
 gill ar*es4  ,! rema9+ five visc]al    
ar*es diff] little 9 _! con/ruction4    
,dorsally1 ea* has a flat1 sickle-%ap$  
ph>yngo-bran*ial c>tilage atta*$ to !   
v]tebral column by fibr\s b&s4 ,!       
ph>yngo-bran*ials ( ! la/ two ar*es are 
fus$4 ,v5trad to ea* ph>yngo-bran*ial is
 an epibran*ial c>tilage4 ,! next segm5t
 ( ea* ar* is =m$ by ! c]atobran*ial    
c>tilage4 ,all ! epibran*ials &         
c]atobran*ials except ^? ( ! fif? ar*   
be> sl5d] bran*ial rays4 ,! v5tral ends 
( ! c]atobran*ials articulate ) ea* o!r1
 ! fir/ be+ atta*$ to ! c]atohyal by    
ligam5t4 ,! second1 ?ird1 & f\r? ar*es h
 ano!r m v5tral s]ies ( c>tilages1 !    
hypobran*ials4 ,! l[] ends ( !          
hypobran*ials are atta*$ to a l>ge m$ian
 plate1 ! basibran*ial4 ,! f\r?         
c]atobran*ial jo9s ! ?ird hypobran*ial1 
:ile ! c]atobran*ials ( ! fif? ar* are  
atta*$ to ! basibran*ial directly4 ,!   
basibran*ial is compos$ ( two segm5ts   

closely unit$ by ligam5t2 ! ant]ior "o  
n>r[1 ! po/]ior broad & flat 9 front1   
tap]+ to a %>p po9t beh9d4  ,%ort tee? (
 c>tilage1 call$ gill rak]s1 project    
into ! ph>ynx f ! inn] edges ( ! ar*es4 
,a dorsal & a v5tral s]ies (            
extra-bran*ial c>tilages1 ?91 sl5d]     
plates1 lie on ! ext]nal side ( ea* gill
 ar*4  ,,pectoral ,,girdle ,,& ,,f94    
,remove f ! body ! pectoral girdle1 ) ! 
f9s atta*$1 & c>efully scrape (f !      
muscles f ! c>tilag9\s p>ts4 ,x w be    
f\nd t ! support ( ! f9 is p>tly (      
c>tilag9\s plates & rods1 p>tly ( horny 
fibres 7d]mal f9-rays7 :i* ov]lie !     
extremities ( ! c>tilages & ext5d to !  
edges ( ! f94 ,^! fibres are 9 two      
lay]s1 "o b5ea? ! sk9 ( ea* side4 ,!y   
are =m$ 9 ! d]mis4 ,a simil> arrangem5t 
( horny fibres is f\nd 9 all ! o!r f9s4 
,! pectoral girdle passes across !      
v5tral surface ( ! body & upw>d on ea*  
side to ! level ( ! v]tebral column4 ,! 
/\t v5tral b> pres5ts num]\s facets = ! 
orig9 & ins]tion ( muscles4 ,! articul> 

surfaces = ! pectoral f9s are well up on
 ! sides ( ! girdle4 ,! sl5d] dorsal end
 ( ea* side ( ! girdle consi/s ( a      
sep>ate b> ( c>tilage1 movably          
articulat$ to ! l[] portion4 ,! asc5d+  
limb ( ! girdle1 f ! f9 articulations to
 ! base ( ! c>tilage j m5tion$1 is call$
 ! scapul> portion2 ! small b> is !     
supra-scapul>2 ! v5tral b> betwe5 ! f9  
articulations is ! coracoid portion4  ,!
 c>tilag9\s skeleton ( ! pectoral f9    
consi/s prim>ily ( a r[ ( ?ree basal    
c>tilages1 all articulat+ proximally ) !
 girdle4 ,! middle basal is mu* ! l>ge/4
 ,di/al to ! basals are ?ree r[s ( rod-l
 radial c>tilages1 ! proximal r[ be+    
articulat$ to ! basals4  ,,pelvic       
,,girdle ,,& ,,f94 ,remove ! pelvic     
girdle f ! body ) ! pelvic f9s atta*$1 &
 clean away ! muscles4  ,! pelvic girdle
 consi/s ( an almo/ /raight b> (        
c>tilage1 slightly ?ick] at its middle  
?an at its ends1 :i* lies transv]sely 9 
! v5tral wall ( ! abdom54 ,to ea* end is
 atta*$ a long basal c>tilage :i* lies 9

 ! f91 close to & p>allel ) its inn]    
m>g94 ,a proximal s]ies ( sl5d] radial  
c>tilages is atta*$ to ! lat]al side ( !
 basal2 a di/al s]ies ( v %ort radials  
lies outside ( ! fir/ s]ies1 :ile !     
portion ( ! f9 beyond ^! is support$ by 
! d]mal f9-rays4  ,,fir/ ,,dorsal ,,f94 
,remove ! mass ( muscles on bo? sides ( 
! base ( ! f9 d[n to ! v]tebral column4 
,! pr9cipal c>tilages ( ! f9 lie 9 !    
m$ian connective tissue septum :i*      
sep>ates ! dorsal musculature ( ! two   
sides ( ! body4 ,! basal c>tilages ( !  
f9 are atta*$ to ! v]tebral column by   
means ( ?is septum4 ,x is be/ to remove 
! und]ly+ portion ( ! column ) ! f94 ,! 
c>tilages c !n be scrap$ p]fectly clean4
 ,! skeleton ( ! f9 is compos$ ( ?ree   
r[s ( c>tilages3 7#a7 a basal r[ consi/+
 ( "o v l>ge1 flat plate & two or ?ree  
small] ones po/]ior to x2 7#b7 an       
int]m$iate r[ ( sev]al plates ( ne>ly   
equal size2 & 7#c7 a di/al r[ ( sev]al v
 small plates4 ,! int]m$iate & di/al r[s
 ext5d beyond ! body musculature into ! 

base ( ! f94 ,! rema9d] ( ! f9 is       
support$ by ! d]mal rays4 ,9 front ( !  
c>tilages :i* h be5 m5tion$ is ! /rong  
sp9e ( d5t9e 7see p4 #e71 ) its free    
portion %ea!d by an enamel-l cov]+4     
,,second ,,dorsal ,,f94 ,remove ?is f ! 
body 9 ! same mann] z ! fir/ dorsal4    
,its /ructure foll[s ! same g5]al plan1 
! diff]5ces be+ m9or ones ( %ape1 size1 
& numb] ( plates4 ,sev]al ?9 c>tilag9\s 
plates are sometimes =m$ 9 ! m$ian      
septum 9 front ( ! sp9e4  ,,caudal ,,f94
 ,only "o side ( ! caudal f9 %\ld be    
clean$1 z :5 bo? sides are clean$ !re is
 dang] ( break+ ! delicate c>tilages4 ,!
 c>tilag9\s skeleton ( ! caudal f9      
consi/s ( a r[ ( sl5d] rods along !     
dorsal side ( ! v]tebral column1 ext5d+ 
to its tip4 ,!re are no c>tilag9\s      
elem5ts 9 ! f9 v5tral to ! v]tebral     
column4 ,by f> ! great] "p ( ! caudal f9
 is support$ by ! two lay]s ( horny     
f9-rays only4                           
,,musculature  ,dissect ! sk9 (f ! head1
 neck1 & body to back ( ! pectoral f9s4 

,obs]ve fir/ ! musculature ( ! dorsal   
side ( ! neck & ( ! body back ( ! bases 
( ! pectoral f9s1 notic+ t x is compos$ 
( n>r[1 zigzag b&s1 call$ myom]es4 ,:]e 
^! are fully develop$ !y ext5d f !      
mid-dorsal to ! mid-v5tral l9e4 ,note   
c>efully ! relation ( correspond+       
myom]es ( ! two sides1 ! exact c\rse ( a
 s+le myom]e1 & ! direction ( ! muscle  
fibres 9 a typical myom]e4 ,obs]ve also 
t ! muscles above ! level ( ! v]tebral  
column =m a ?ick mass1 :i* is frequ5tly 
ref]r$ to z ! dorsal musculature2 !     
muscle bel[ ?is level may be            
correspond+ly ref]r$ to z ! v5tral      
musculature4 ,z ! muscles describ$ bel[ 
are dissect$ ! me*anical effect ( ea*   
%\ld be det]m9$4  ,,musculature ,,( ,,! 
,,head ,,& ,,neck4 ,on ! lat]al & v5tral
 surfaces ( ! neck ! prim>y relations ( 
! myom]es are mu* modifi$ by !          
developm5t ( num]\s special muscles1 yet
 "h & !re traces ( ! metam]ic arrangem5t
 /ill %[4 ,imm$iately b5ea? ! sk9 is a  
?9 %eet ( muscle cov]+ mo/ ( ! v5tral & 

lat]al surfaces ( ! ?roat z f> back z ! 
pectoral girdle4 ,on ! v5tral surface a 
triangul> space is left 9 front ( !     
pectoral b>2 on ! sides ( ! neck ! %eet 
ext5ds back to ! la/ gill-cleft2        
dorsally1 x rea*es to ! upp] extremities
 ( ! gill p\*es4 ,?is is ! con/rictor   
sup]ficialis muscle4 ,x is atta*$ to    
fasciae dorsally & v5trally1 & to !     
extra-bran*ial c>tilages4  ,! con/rictor
 sup]ficialis consi/s ( six metam]ic    
segm5ts4 ,! f\r po/]ior ones are        
di/9ctly limit$ by ! gill-slits &       
extra-bran*ial c>tilages4 ,! second is  
ant]ior to ! fir/ gill slit1 ! l>ge/ (  
all1 ) di/9ct dorsal & v5tral portions  
ext5d+ =w>d above & bel[ ! jaws4 ,! fir/
 is recogniz$ z consi/+ ( two di/9ct    
p>ts1 on ! dorsal & v5tral surfaces ( ! 
head4 ,! dorsal portion is a small curv$
 muscle on ! ant]ior wall ( ! spiracle1 
ext5d+ f ! ext]nal surface ( ! auditory 
capsule to ! inn] surface ( ! l[] jaw4  
,x lies close aga9/ ! levator m>illae   
sup]ioris 7see bel[74 ,on ! v5tral      

surface ( ! ?roat ! po/]ior con/rictor  
muscles ( ! two sides are sep>at$ by a  
l>ge triangul> area4 ,9 front ( ?is !   
v5tral portions ( ! fir/ & second       
con/rictors meet 9 a m$ian aponeurosis1 
f :i* _! fibres ext5d transv]sely1 ^? ( 
! fir/ to ! m&ibul> c>tilage1 ^? ( !    
second to ! hyoidean c>tilage4 ,! fir/  
con/rictor lies v5tral or sup]ficially  
to1 & l>gely cov]s ! second4 ,reflect ! 
fir/ con/rictor f ! aponeurosis outw>d1 
& demon/rate ! two lay]s ( muscle4 ,x w 
be not$ t ! second to six? con/rictors  
consi/ ( unit$ dorsal1 lat]al & v5tral  
portions1 :ile ! fir/ is r$uc$ to widely
 sep>at$ dorsal & v5tral p>ts4  ,on ea* 
side ( ! head1 j outside ! angle ( !    
m\?1 is a l>ge1 ?ick muscle aris+ f !   
lat]al surface ( ! cranium1 & ins]t$ ^u 
! out] surface ( ! m&ible1 ! adductor   
m&ibul>is4  ,9 front ( ! small dorsal   
con/rictor sup]ficialis #a1 & sc>cely   
sep>at$ f x1 is ! /rong levator maxillae
 sup]ioris1 :i* ext5ds f ! lat]al       
surface ( ! auditory capsule to ! dorsal

 edge ( ! palato-quadrate c>tilage4     
,eugaleus4 ,! dorsal portion ( !        
con/rictor sup]ficialis #b rea*es above 
! spiracle to ! po/orbital process4     
,reflect+ x1 ! adductor hyom&ibulae is  
se5 beh9d ! spiracle1 aris+ f ! upp] "p 
( ! side ( ! auditory capsule & ins]t$  
on ! end ( ! hyom&ibul> c>tilage4 ,!    
levator palpebrae inf]ioris arises "u ! 
orig9 ( ! levator hyom&ibulae1 & passes 
=w>d & d[nw>d betwe5 ! spiracle &       
po/orbital process1 to ins]t 9 ! po/]ior
 end ( ! l[] eyelid4 ,! depressor       
palpebrae sup]ioris arises f ! fascia   
dorsal to ! spiracle1 passes m$iad to ! 
levator palpebrae inf]ioris1 upw>d &    
=w>d1 to ins]t 9 ! po/]ior end ( ! upp] 
eyelid4 ,remove ^! muscles4 ,!          
infra-orbital canal passes m$iad to !   
muscles ( ! eyelids4 ,! levator maxillae
 sup]ioris lies betwe5 ! spiracle & !   
orbit4 ,beh9d x is a small slip ( muscle
 ext5d+ f ! ant]ior wall ( ! spiracle to
 ! lat]al surface ( ! auditory capsule  
:i* seems to repres5t ! con/rictor      

sup]ficialis dorsalis #a4  ,a ?9 %eet ( 
muscle cov]s ! ant]ior face ( ea*       
int]-bran*ial septum4 ,at ! surface ^!  
pass into ! con/rictor sup]ficialis1 &  
are evid5tly portions ( ! latt] muscle1 
?\gh !y are nam$ ! musculi              
int]bran*iales4  ,above ! con/rictor    
sup]ficialis1 ly+ on ! side ( ! neck    
betwe5 x & ! dorsal musculature1 is a   
broad trapezius muscle4 ,x arises f !   
fascia cov]+ ! lat]al surface ( ! dorsal
 musculature4 ,its fibres pass obliquely
 d[nw>d & backw>d1 m$iad to ! po/]ior   
gill p\*es1 to ins]t ^u ! ant]ior edge (
 ! scapul> portion ( ! pectoral girdle4 
,! ant]ior portion ( ! trapezius is also
 ins]t$ ^u ! epibran*ial ( ! fif? gill  
ar*4  ,j 9 front ( ! m\? is a pair (    
/rong muscles 7levator labialis         
sup]ioris71 ea* aris+ f ! v5tral surface
 ( ! cranium close to ! m$ian l9e4 ,!y  
pass into /rong t5dons :i* are ins]t$   
among ! fibres ( ! v5tral portion ( !   
adductor m&ibulae4 ,! muscle mass 9     
front ( ! m\? & ! l[] "p ( ! adductor   

m&ibul>is ?us =m ! two bellies ( a      
diga/ric muscle1 ) ! t5don betwe5 !m4   
#b,remove ! v5tral portions ( ! fir/ &  
second sup]ficial con/rictors & cle> !  
mass ( muscles ly+ betwe5 ! coracoid    
portion ( ! pectoral girdle & ! m&ible4 
,imm$iately 9 front ( ! girdle are two  
l>ge muscles1 ! coraco-arcuales         
communes1 ^: fibres run inw>d & =w>d4   
,^! muscles cov] ! v5tral surface ( !   
p]ic>dium1 to ! wall ( :i* _! m$ian     
fibres are atta*$1 :ile ! lat]al fibres 
are atta*$ ar\nd ! v5tral ends ( ! gill 
ar*es4  ,footnote #b3    ,!             
coraco-m&ibul>is1 coraco-hyodeus1       
coraco-arcualis communis1 &             
coraco-bran*ialis muscles %\ld be       
dissect$ z a prelim9>y   op]ation to    
foll[+ ! v5tral aorta & its bran*es4  ,9
 front ( ! coraco-arcuales communes are 
?ree l>ge longitud9al muscles4 ,! m$ian1
 unpair$ "o1 aris+ f ! fascia betwe5 !  
coraco-arcuales communes & ins]t$ ^u !  
po/]ior surface ( ! l[] jaw1 is !       
coraco-m&ibul>is4 ,! o!r two1 :i* lie   

dorsal to & outside ( !                 
coraco-m&ibul>is1 are ! coraco-hyoidei4 
,!y arise f ! fasciae cov]+ ! ant]ior   
ends ( ! coraco-arcuales communes &     
po/]ior p>ts ( ! coraco-bran*iales1 &   
ins]t ^u ! basihyal4  ,dissect out !    
coraco-m&ibul>is & coraco-hyoidei1 not+ 
p>ticul>ly ! =m & place ( orig9 ( !     
latt]4 ,dorsal to ! coraco-hyoidei are !
 fir/ divisions ( ! "r & left           
coraco-bran*ialis muscles1 :i* arise f  
fascia cov]+ ! ant]ior ends ( !         
coraco-arcuales communes1 & are ins]t$  
^u ! v5tral extremity ( ! c]atohyal     
c>tilage4 ,notice t !y pass dorsad to ! 
ant]ior bran*es ( ! aorta1 & t ! aorta  
itself c be expos$ betwe5 !m4  ,remove !
 coraco-arcualis communis by dissect+ x 
f ! pectoral girdle & reflect+ x =w>d4  
,! o!r f\r divisions ( !                
coraco-bran*ialis are n[ reveal$1 atta*$
 to ! lat]al surface ( ! p]ic>dium & !  
lat]al portion ( ! coracoid4 ,!         
divisions ( ! muscle are cle>ly sep>at$ 
only ne> _! ins]tions4 ,! second1 ?ird1 

& f\r? coraco-bran*ials are atta*$ to ! 
hypobran*ial c>tilages ( ! second1 ?ird 
& f\r? visc]al ar*es4 ,! fif? division  
is ins]t$ ^u ! lat]al portion ( !       
basibran*ial & ! exp&$ m$ial end ( !    
fif? c]atobran*ial4  ,! fir/ aortic     
bran* passes v5tral to ! fir/           
coraco-bran*ial4 ,! second aortic bran* 
passes betwe5 ! fir/ & second           
coraco-bran*ials4 ,! ?ird aortic bran*  
passes betwe5 ! second & ?ird           
coraco-bran*ials4 ,! f\r? aortic bran*  
passes betwe5 ! ?ird & f\r?             
coraco-bran*ials4  ,expose ! dorsal ends
 ( ! gill ar*es by cle>+ away muscles & 
o!r tissues betwe5 ! gill p\*es & !     
sp9al column4 ,two sets ( f\r small     
muscles 7int]>cuales7 w be f\nd connect$
 ) ! bran*ial c>tilages4 ,! second1 ?ird
 & f\r? m$ial int]>cuales ext5d f !     
po/]ior surfaces ( ph>yngo-bran*ial     
c>tilages #a1 #b1 & #c1 to ! dorsal     
surfaces ( ph>yngo-bran*ials #b1 #c1 #d1
 & #e4 ,! fir/ m$ial int]>cuale arises f
 ! "u surface ( ! cranium & ins]ts on ! 

upp] end ( ! fir/ ph>yngo-bran*ial4  ,! 
lat]al int]>cuales lie imm$iately bel[ !
 m$ials4 ,! fir/ has a d\ble orig91 mo/ 
( ! fibres aris+ f ! l[] "p ( ! po/]ior 
edge ( ! fir/ ph>yngo-bran*ial2 a small]
 bundle f ! ant]ior edge ( ! second     
ph>yngo-bran*ial4 ,its ins]tion is along
 ! dorsal surface ( ! fir/ epibran*ial  
c>tilage4 ,! second & ?ird lat]al       
int]>cuales are l ! fir/1 b s9ce ! f\r? 
& fif? ph>yngo-bran*ials are fus$1 !    
orig9 ( ! f\r? lat]al int]>cuale is n   
divid$4  ,! circul> muscles ( !         
oesophagus are /rongly atta*$ to ! la/  
ph>yngo-bran*ial4  ,,musculature ,,( ,,!
 ,,pectoral ,,f94 ,! dorsal muscle ( !  
f9 7levator-retractor7 arises mo/ly f ! 
scapul> portion ( ! girdle1 ) a small "p
 aris+ f ! fascia cov]+ ! lat]al        
musculature ( ! body4 ,x is atta*$ 9    
fasciculi to ! dorsal surfaces ( !      
c>tilag9\s rays4 ,! v5tral muscle       
7depressor-protractor7 arises f ! m$ian 
portion ( ! girdle & is ins]t$ ^u !     
c>tilag9\s rays 9 simil> fasciculi4 ,a  

portion ( ! lat]al body muscles is      
ins]t$ ^u ! scapul> portion ( ! girdle4 
,,musculature ,,( ,,! ,,pelvic ,,f94    
,v5tral surface3 ,an adductor muscle has
 orig9 ^u ! po/]o-lat]al edge ( !       
girdle2 x is ins]t$ ^u ! ant]o-m$ial    
surface ( ! basal c>tilage ( ! f94 ,!   
depressor muscle consi/s ( small        
fasciculi1 ea* correspond+ to a         
c>tilag9\s ray4 ,!y arise f !           
po/]o-lat]al surface ( ! basal c>tilage 
& are ins]t$ ^u ! di/al extremities ( ! 
rays4  ,dorsal surface3 ,! abductor     
arises f ! fascia cov]+ ! trunk muscles1
 & ins]ts ^u ! fascia cov]+ ! intr9sic  
muscles ( ! dorsal side ( ! f94 ,^!     
latt] 7levatores7 are arrang$ 9 exactly 
! same mann] z ! fasciculi ( !          
depressor4  ,,musculature ,,( ,,!       
,,dorsal ,,f9s4 ,a %eet ( muscle is     
atta*$ to ea* side ( ! ant]ior dorsal   
f91 ext5d+ ne>ly up to ! bases ( ! d]mal
 f9-rays4 ,?is muscle passes d[nw>d     
betwe5 ! dorsal body musculature ( ! two
 sides4 ,"p ( ! fibres arise f ! fasciae

 cov]+ ! m$ial surfaces ( ! body        
muscles1 "p f ! basal c>tilage ( ! f9   
itself4 ,!y are ins]t$ ^u ! lat]al      
surfaces ( ! broad c>tilag9\s f9-rays4  
,! muscles ( ! po/]ior dorsal f9 are    
exactly simil> 9 arrangem5t4            
,,musculature ,,( ,,! ,,caudal ,,f94    
,!re is no special musculature = !      
dorsal portion4 ,a n>r[1 b&-l muscle is 
f\nd on ea* side ( ! v5tral portion1    
wide/ above ! triangul> v5tral lobe4 ,! 
fibres ( ?is muscle arise ^u ! flatt5$1 
exp&$ ends ( ! haemal sp9es4 ,!y pass   
obliquely backw>d & upw>d to be ins]t$ 9
 ! fascia und]ly+ ! sk94                
----------------------------------------
--------------------------------        
,transcrib]'s ,notes3      ,miss+ or    
obscur$ punctuation 0 sil5tly correct$4 
,typographical errors 7 sil5tly         
correct$4      ,inconsi/5t spell+ &     
hyph5ation 7 made consi/5t only       :5
 a pr$om9ant =m 0 f\nd 9 ?is book4      
,text t 0 9 italics is enclos$ by       
und]scores 7italics74