Ix ALIMENTARY CANAL 255 
and the appearance of gastric glands in the wall of the latter 
cavity afford the only distinction between the two regions. The 
Fig. 153.—Dissection of a 
male Dog- Fish (Sey/- 
lium). he left side of 
the body is cut away 
to the median plane so 
as to expose the ab- 
dominal and pericardial 
cavities and the neural 
canal in their whole 
S length. The alimentary 
= canal and the liver have 
been drawn downwards, 
and the oral cavity, the 
pharynx, part of the 
intestine, and the cloaca 
have been opened. The 
cartilaginous parts of the 
skeleton are dotted, and 
the calcified portions of 
the vertebral centra are 
black. abd.cav, Aldo- 
minal cavity ; au, au- 
ricle ; 0.67, basi- bran- 
chial; b.hy, basi-hyal ; 
c.art, conus arteriosus ; 
cd.a, caudal artery ; 
cd. st, cardiac part of the 
stomach ; ed.v, caudal 
vein; cl, cloaca; cn, 
centrum ; ¢c7, cranium ; 
crb, cerebellum ; d.ao, 
dorsal aorta ; dien, tha- 
lamencephalon ;_— epid, 
epididymis ; fon, fonta- 
nelle; gul, oesophagus ; 
ha, haemal arch; 
i.br.a—_-i.br.a,° internal 
gill-clefts ; int, intes- 
tine; kd, kidney ; 1, 
lower jaw ; /./7, left lobe 
of liver ; med.obl, me- 
dulla oblongata; mes, 
mesentery ; ”.a@, neural 
arch} n.cav, neural 
eanal; olf, olfactory 
lobes ; opt.l, optic lobes ; 
pan, pancreas ; ped.cav, 
pericardial cavity ; pet.a, 
pectoral arch ; ph, 
pharynx ; pin, pineal 
= body ; p.n.d, vestigial 
> Miillerian duet; prs, 
prosencephalon ; pty, 
pituitary body ; pv.a, pelvic arch ; pyl.st, pyloric portion of the stomach ; 7, rostrum ; 7./7, right 
lobe of liver ; rct.g/, rectal gland ; sp, spiracle ; sp.cd, spinal cord ; spl, spleen ; sp.s, Sperm 
sac ; sp.vl, spiral valve ; s.v, sinus venosus ; ¢7g, tongue ; ¢s, testis ; U.g.8, urino-geuital sinus ; 
u.j, wpper jaw ; wr, metanephric duct ; v, ventricle ; v.ao, ventral aorta ; v.def, vas deferens 
or mesonephric duct ; vs.sem, vesicula seminalis. (From Wiedersheim, after T. J. Parker.) 
ur 
US. SE, 
udef Ka 
\ LA 
% 
ON cre 
