25 



mal food may be batracliians, lislies, crustaceans, mollnsks, 

 insects and their larvae, etc. 



A fish's diet may be restricted to but one of these vari- 

 ous classes, or it may go through the entire bill of fare 

 like a Christian ; but the general character of the food of 

 a fish may usually be determined by the structure and 

 position of its teeth, so that an examination of the teeth 

 of a lish will indicate whether it is herbivorous, carnivo- 

 rous, or omnivorous. 



The teeth of most fishes, when they exist in the mouth, 

 may be in patches or bands of equal teeth, and may be 

 either villiform or brush-like, setiform or bristle-like, 

 cardiform or card-lilve, or rasp-like, or they may be of un- 

 equal size and sharp and conical, compressed or lancet- 

 shaped, or blunt, broad, or truncated, molar-like, canine, 

 incisors, etc. The teeth may be situated on the jaws, 

 vomer, palatines, pterygoids, tongue and gill arches, or 

 the mouth may be entirely toothless, and the teeth con- 

 fined to the pharyngeal bones of the throat, or they may 

 exist in the oesophagus, or gullet. 



Fishes with unequal, sharp, conical, or canine teeth are 

 piscivorous, and feed upon small fishes, which they swal- 

 low whole ; and those with lancet-shaped teeth, while also 

 piscivorous, cut or lacerate their prey before swallowing 

 it. Fishes with pavements of molar-like teeth feed upon 

 crustaceans and mollusks, while those with toothless jaws 

 are herbivorous, or if carnivorous, feed upon minute ani- 

 mal organisms, and are in no sense piscivorous. 



Beginning with toothless fishes, that is, with no teeth in 

 the moutli, are the minnows {Cyprinidte), and suckers 

 {Gatosto7nid(B)\ they are both herbivorous and carnivorous. 

 All of the minnows, with intestines several times longer 

 than their bodies, feed principally upon vegetable matter, 

 and the others upon insects and their larv^ and minute 

 crustaceans {Entomostraca). Minnows have a few very 

 small pharyngeal teeth, with or without grinding surfaces. 



