418 ANATOMY OF VERTEBRATES. 



obtuse processes from the inner side of the cardia in this fish. In 

 the Gillaroo Trout the ascending or pyloric half of the bent or 

 siphonal stomach has its muscular parietes unusually thickened, 

 by which it is enabled to bruise the shells of the small fluviatile 

 testaceans that abound in the streams to which this variety of 

 trout is peculiar. 1 The pyloric portion of the stomach is very 

 muscular in the Indian Whiting (Johnius), and in some species of 

 Scomber : but the modification which gives the stomach the true 

 character of a gizzard is best seen in the Mullets (Mitgil). The 

 cardiac portion here forms a long cul de sac ; the pyloric part is 

 continued from the cardiac end of this at right angles, and is of a 

 conical figure externally ; but the cavity within is reduced almost 

 to a linear fissure by the great developement of the muscular 

 parietes, which are an inch thick at the base of the cone ; and this 

 part is lined by a thick horny epithelium. 2 In the Herring the ductus 

 pneumaticus of the swim-bladder is continued from the attenuated 

 extremity of the cardiac end of the stomach, fig. 281, b. In the 

 Basking-shark the contracted pyloric division of the stomach, figs. 

 278, c, and 284, f, communicates by a narrow aperture with a 

 second small rounded cavity, fig. 284, f , which opens by a narrow 

 pylorus into the short and capacious duodenum, fig. 278, f, 284, q. 



Such are the observed extremes of the modifications of the 

 stomach in Fishes, which it will be seen, therefore, are far from 

 according with or paralleling those of the dental system. There 

 is often, indeed, no essential difference of form in the stomach of 

 a fish with exclusively laniary teeth, e. g. the carnivorous Salmon, 

 and in that of one with exclusively molar teeth, e. g. the herbi- 

 vorous Carp. The vFtobates, whose teeth form a crushing 

 pavement, has a stomach similar in shape and size to that in the 

 common Ray, in which every tooth is conical and sharp-pointed. 



The inner surface of the stomach presents few modifications in 

 Fishes : it is usually smooth ; rarely reticulate, as in the Gym- 

 n'otus ; still more rarely papillose. The lining membrane is 

 thrown into wavy longitudinal rugae in the cardiac portion of 

 the stomach of most Sharks, fig. 278. The gastric follicles are 

 conspicuous, especially in the pyloric portion of the stomach in 

 many Fishes, as, e. g., the Gurnards, Blennies, and Lump-suckers. 

 The circular pyloric valve is commonly well developed, and has 

 sometimes a fimbriated margin. The solvent power of the gastric 

 secretion is conspicuously exemplified in Fishes : if a voracious 

 species be captured after having swallowed its prey, the part lodged 

 in the stomach is usually found more or less dissolved, whilst 



1 xcn. p. 126. 2 xx, vol. i. p. 141, prep. no. 502. 



