DIGESTIVE SYSTEM 01" VISHES. 235 



peculiar.* 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 {3Iugil). 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 

 development 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 

 (prep. 502). In the Herring the ductus pneumaticus of the swim- 

 bladder is continued from the attenuated extremity of the cardie end 

 of the stomach. In the Basking-shark the contracted pyloric division 

 of the stomach (Jiff. 65./) communicates by a narrow aperture with 

 a second small rounded cavity (f), which opens by a narrow pylorus 

 into the short and capacious duodenum ({/). 



These are the observed extremes of the modifications of the sto- 

 mach in Fishes, which it will be seen, therefore, are far from accord- 

 ing or parallelising those of the dental system. There is often, in- 

 deed, 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 herbivorous Carp. The 

 -ZEtobates, 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 Gymnotus 

 (prep. 500.); still more rarely papillose. The lining membrane is 

 thrown into wavy longitudinal rugfe in the cardiac portion of the 

 stomach of most Sharks. 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 py- 

 loric valve is commonly well developed and has sometimes a fim- 

 briated margin. The solvent power of the gastric secretion is 

 conspicuously exemplified in Fishes : if a voracious species be cap- 

 tured after having swallowed its prey, the part lodged in the stomach 

 is usually found more or less dissolved, whilst that which is in the 

 oesophagus is entire ; and, in specimens dissected some hours after 

 death, one may observe, what Hunter so well describes, " the di- 

 gesting part of the stomach itself reduced to the same dissolved 

 state as the digested part of the food." f This surrender of the 

 dead membranes of the stomach to the solvent power of the pre- 

 viously secreted gasti'ic juice is well exemplified in the preparation 

 of the Shark's stomach, N. 507. n. 



* J. Hunter, xcii. p. 120'. t '^f"- P- 120. 



