278 TEXT-BOOK OF ZOOLOGY 



The mode in which it is adapted to an aquatic life is evident from 

 what has been already stated under this head in our general remarks on 

 fishes. 



B. Structure of Body, and Food. 



The carp is by no meanB a fastidious feeder ; indeed, it will consume 

 anything that is eatable : portions of green plants, mud with its various 

 decaying and putrefying materials, worms, insects and their larvae, 

 snails, small fresh-water Crustacea, which often occur in ponds and 

 rivers in enormous quantities (Copepoda) — see herring and illustration, 

 p. 285 — and so-called "water fleas" (Daphnia) — which see — and anything 

 else, in fact, which may be found in the water. Domesticated carp are 

 fed with all sorts of kitchen refuse, peas, beans, etc. The carp, in fact, 

 is omnivorous, " the pig among fishes." (How far is this omnivorous 

 habit an advantage to the distribution of the fish, and of importance to 

 its artificial culture ?) 



(a) The carp, accordingly, is not obliged to be a rapid swimmer, like a 

 predaceous fish, e.g., the pike (which see). Hence its body is relatively 

 stout (prove this more fully) . Carp reared artificially are higher-backed, 

 and consequently more fleshy, while those living in a Btate of nature are 

 longer and narrower (explain this difference). 



(b) Slow motion from place to place is effected primarily by the 

 pectoral fins, which accordingly have the form of large broad oars. 



(c) The carp, not being obliged to seize, hold, and swallow large-sized 

 prey, has a narrow and toothless mouth. (With regard to protrusibility 

 of jaws, see p. 271, Section b.) 



(d) Vegetable substances, in order to be digested, require to be masti- 

 cated (see Part I., p. 102, Section 2). In the carp mastication is effected 

 by means of the pharyngeal bones. The superior pharyngeal bones, ac- 

 cordingly, have the form of broad plates, while the inferior ones are 

 armed with teeth, having broad crowns surmounted with folds of enamel. 

 (Compare with herbivorous mammals.) The posterior part of the oral 

 cavity, the masticatory chamber, in which the food is divided up, is closed 

 by muscles both at its anterior oral and its posterior pharyngeal termina- 

 tion. (Why is this necessary? Eemember what was said about the 

 water of respiration which streams through the mouth.) 



(e) The intestine is long, as in all herbivorous animals (see Part I., 

 p. 102, Section 1, /). 



(f) The mouth is surrounded by fleshy lips, and furnished with from 

 two to four " barbels " on the upper lip, which serve as tactile organs in 

 the searching of the mud. 



(g) The predominance of vegetable substances in the food of the carp 



