41G 



ANATOMY OF VERTEBRATES. 



the forepart of the oesophagus by a second orifice much smaller 

 than the first, and having a tumid valvular margin. 



The cardiac orifice of the stomach is occasionally defined by a 

 constriction, as in the Planirostra and Mormyrus, fig. 280 : but 

 an increased expansion with increased vascularity and a more, 

 delicate epithelial lining of the mucous membrane more usually 

 indicate, in Fishes, the beginning of the digestive cavity. The 

 stomach is a simple and commonly an ample cavity, with a 

 great disproportion in the diameters of the cardiac and pyloric 

 orifices ; in the Cornish Porbeagle- Shark, for example, the cardiac 

 entry will readily admit a child's head, whilst the pyloric outlet 

 will barely allow of the passage of a crow-quill. 



There are two predominant forms of the stomach in Fishes, viz. 

 the ' siphonal ' and the ' cascal.' In the first it presents the form of 

 a bent tube or canal, as in the Turbot, fig. 287, a, b, Flounder, 

 Sole, Cod7 Haddock, Salmon, fig. 286, a, b, Carp, Tench, Ide, Lump- 

 fish, File-fish, Lepidosteus, Sturgeon, Paddle-fish, and most Plagio- 



278 



Alimentary canal of Shark, cci.xvi. 



stomes, fig. 278 : in the second form the cardiac division of the 

 stomach terminates in a blind sac, and the short pyloric portion is 

 continued from its right side, as in the Perch, the Scorpama, the 

 Gurnards, the Bull-heads, the Smelts, the Whiting, fig. 285, the 

 Angler, the Pike, the Lucioperca, the Sword-fish, fig. 282, the 

 Silurus, the Herring, the Sprat, fig. 288, the Pilchard, the 

 Conger, the Murama, and the Polypterus, fig. 279. A transi- 

 tional form, in which the pyloric end is bent so abruptly upon 



