ALIMENTARY CANAL 



253 



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 (Scyl- 

 lium). The left side of 

 the body is cut away 

 to the median plane so 

 as to expose the ab- 

 dominal and pericardia! 

 cavities and the nenral 

 canal in their whole 

 length. The alimentary 

 canal and the liver have 

 been drawn downwards, 

 and the oral cavity, the 

 pharynx, part of tlie 

 intestine, and the cloaca 

 have been opened. The 

 cartilaginous parts of the 

 skeleton are dotted, and 

 the calcined portions of 

 the vertebral centra are 

 bl:ick. abd.cav, Abdo- 

 minal cavity ; au, au- 

 ricle ;- b.br, basi - bran- 

 chial ; b.hy, basi-hyal ; 

 c.art, couus nrteriosus ; 

 cd.a, caudal artery ; 

 cd.st, cardiac part of the 

 stomach ; cd.v, caudal 

 vein ; d, cloaca ; en, 

 centrum : cr, cranium ; 

 crb, cerebellum ; '/.". 

 dorsal aorta ; dien, tha- 

 lamencephalon ; </""', 

 epididymis ; fun, fonta- 

 nelle ; gul, oesophagus ; 

 h.a, haemal arch ; 

 i.br.a 1 i.br.a, 5 internal 

 gill -clefts ; int, intes- 

 tine ; M, kidney ; l.j, 

 lower jaw ; Llr, left lobe 

 of liver ; med.nlil, me- 

 dulla oblongata ; mes, 

 mesentery ; n.a, neural 

 arch ; n.cav, neural 

 canal ; olf.l, olfactory 

 lobes ; opt. I, optic lobes ; 

 pan, pancreas ; pa/. <<, 

 pericardial cavity ;pct.a, 

 pectoral arch ; ph, 

 pharynx ; pin, pineal 

 body ; p.n.d, vestigial 

 Miillerian duct ; prs, 

 prosencephalon ; pty, 

 pituitary body ; pv.a, pelvic arch ; pyl.st, pyloric portion of the stomach ; /, rrtrum ; r.lr, right 

 lobe of liver ; rct.yl, rectal gland ; sp, spiracle ; sp.cd, spinal cord ; spl, spleen ; sp.s, sperm 

 sac ; sp.vl, spiral valve ; s.v, sinus venosus ; tng, tongue ; ts, testis ; u.g.s, urino-geuital sinus ; 

 u.j, upper jaw ; ur, 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.) 



