XVI 



INTRODUCTION. 



and long the peristaltic movements of the alimentary canal ; and the successive regurgitations 

 of the gastric contents produce actions of the pharyngeal jaws, as the half bruised grains 

 come into contact with them, and excite the singular tumefaction and subsidence of the irri- 

 table palate, as portions of the regurgitated food are pressed upon it. The shortness and 

 width of the oesophagus, the masticatory mechanism at its commencement, and its direct 

 terminal continuation with the cardiac portion of the stomach, relate to the combination of an 

 act analogous to rumination, with the ordinary process of digestion, in all fishes possessing 

 these concatenated and peculiar structures." — {Anat. of Vertcb., i. p. 419.) 



Azurine. 



Tench. 



Dace. 



Eiidd. 



Roach. 



Bre.am. 



B.arbel. 



Pomeranian Bream. 



In a letter with which Professor Owen, with his characteristic kindness, some few years 

 ago favoured me, he says, "Continued observations under the rare and difficult circumstances 

 according to which they can be made, have now convinced me, that matters for mastication 

 by throat-chewers come from bchiiid, as those by mouth-chewers from before. And indeed when 

 one comes to consider how thoroughly and regularly the mouth of a fish is washed out by 

 the branchial streams, there needs must be some special arrangement for the masticating 

 machinery in lithophagus and phytophagous fishes. Consider what would be the consequence to 

 the partially broken up coral and pulp, if retained at the back of the mouth, to be pounded 

 piecemeal by the pharyngeals, the rush of two diverging streams through that faucial area 

 ■i-oino- on the while like clockwork. No ! the food, reduced if needful to a size swallowable, is 

 bolted, and the branchial way speedily cleared. Then comes into play that anti-peristaltic 

 rotation of the short gullet, and bit by bit the contents are shed in a tergo between the 

 grinders till all is pulped." 



A fish's intestine is usually short and wide, and more or less convoluted; the mucous 

 membrane presents numerous modifications; it has often a spiral folding (as in the- Sharks), 



