PHARYNGEAL TEETH OF FISHES. 419 



as in the Sunfish. Or the pharyngeal teeth may be crushing 

 teeth of a granular form, as in the Wrasses (Labridce) ; or molari- 

 form, set on stalks, and biting against a horny pad, as in the 

 Carp family (Cyprinidce) ; or of a pavement-like structure, as in 

 the Pseudoscarus muricatus ; or setiform, like bristles, as in the 

 Black Pomfret (Stromateus niger). 



The external teeth and those in the anterior part of the 

 mouth are adapted for seizing the fishes' prey. The pharyngeal 

 teeth are, probably, the principal masticatory organs ; in the 

 Carp family (Cyprinidce) they undoubtedly are. Some Teleostean 

 fishes, e. g. the Twait Shad (Clupea Jinta), are devoid of any 

 pharyngeal teeth. Fish that prey on other fishes and that 

 swallow them whole would have the action of their gastric juices 

 much facilitated for the process of digestion, if the scales of the 

 swallowed fish were scarified and torn by the pharyngeal teeth, 

 as they must be in the process of swallowing, rather than if the fish 

 arrived in the stomach with its scaly covering intact ; while fish 

 that live wholly or partially on crustaceans, which may be called 

 " the staff of life " for fishes, can give them a scrunch in passing 

 through their pharynx that must loosen the shell of the crusta- 

 cean and facilitate digestion. The Wrasses (Labridce) that feed 

 on shell-fish have their granular teeth in the upper and lower 

 pharyngeals adapted to crush the shell, they not being provided 

 with teeth in the front part of the mouth for this work, as is 

 the case in the Sea Bream family (Sparidte). The Carp (Cyprinus 

 carpio), a vegetarian, finds its molariform teeth most useful for 

 the masticating of its food, as do no doubt the rest of this family. 

 The pharyngeal teeth also help largely in working the food down 

 into the oesophagus, especially in those fish that have strongly 

 cardiform teeth ; and as the pharyngeal teeth are surrounded 

 and embedded in mucous membrane, they probably, by their 

 lacerating the skin of the prey, enable a fish to get a taste of 

 what he is eating, a pleasure that fishes are not generally 

 credited with enjoying. 



To form a correct notion of the pharyngeal teeth and their 

 place in the mouth, it would be well to get a general idea of the 

 anatomy of this part. The accompanying diagram may help to 

 impress on the mind the names and general situation of the 

 bones. It is typical of the left half of a fish's gullet. 



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