190 Rumination in Fish. 



KUMINATION IN FISH ; THE SCARUS OF THE 

 ANCIENTS. 



BY EEV. W. HOUGHTON, M.A., F.L.S. 



Rumination, or the power possessed by certain animals of 

 casting up small portions of food from the stomach into the 

 mouth for the purpose of re-mastication, is amongst mammalia 

 normally confined to the ruminant order, comprising the fami- 

 lies GamelidcB, Moschidce-, Camelopardidce, and Bovidce, including 

 the antelopes, sheep, and cattle. I say normally, because, 

 as is well known, certain individuals of the genus homo have 

 been known to possess this power.* Moreover, Professor Owen 

 has, I believe, observed a quasi-ruminant power in some species 

 of kangaroos. It is possible that careful observation may dis- 

 cover occasional instances of abnormal rumination in other 

 orders ; in most of the mammalia there is nothing to prevent 

 the regurgitation of food from the stomach into the mouth for 

 re-mastication, but in some there is a mechanical obstruction, 

 as for instance in the horse, the valvular construction of the 

 entry of whose stomach renders such an act impossible. It 

 appears, however, from the investigations of Professor Owen, 

 that rumination is not confined to the mammalia alone. 

 Certain families of the class Pisces possess a power essentially 

 identical with rumination. 



" The muscular action of a fish's stomach," says our great 

 anatomist, " consists of vermicular contractions, • creeping 

 slowly in continuous succession from the cardia to the pylorus, 

 and impressing a twofold gyratory motion on the contents ; so 

 that, while some portions are proceeding to the pylorus, other 

 portions are returning towards the cardia. More direct con- 

 strictive and dilative movements occur, with intervals of repose, 

 at both the orifices, the vital contraction being antagonized by 

 pressure from within. The pylorus has the power, very evidently, 

 of controlling that pressure, and only portions of completely 

 comminuted and digested food (chyme) are permitted to pass 

 into the intestine. The cardiac orifice appears to have less control 

 over the contents of the stomach ; coarser portions of the food 

 from time to time return into the oesophagus, and are brought 

 again within the sphere of the pharyngeal jaws, and sub- 

 jected to their masticatory and comminuting operations. The 

 fishes which afford the best evidence of this ruminating action 



* A friend of mine when studying in Germany told me of a case of rumination 

 in the school he attended. One of the boys- possessed this very undesirable 

 accomplishment, and in consequence of his persisting in the habit in spite of all 

 remonstrances, he was obliged to leave the school. 



