XX 



INTRODUCTION. 



bones. Sometimes the teeth are uniform in shape on the 

 various bones ; at others differing. One or more of these 

 bones are sometimes without teeth of any sort ; and there 

 are fishes that have no teeth whatever on any of them. The 

 teeth are named according to the bone upon which they are 

 placed ; and are referred to as intermaxillary, maxillary, pala- 

 tine, vomerine, See. depending upon their position. 



A reference to page 3 in the second volume will show the 

 situation of the teeth in the Trout, with five rows on the 

 upper surface of the mouth, and four rows below ; the parti- 

 cular bones upon which these rows are placed are also referred 

 to. The form of the teeth in fishes is various ; in general 

 it represents that of an elongated cone, slightly curved in- 

 wards to assist in holding a prey which is frequently alive. 

 Sometimes the form is that of a short and rounded tubercle, 

 adapted for crushing ; in some fishes the teeth are so small 

 and numerous as to have the appearance of the hairs of a 

 brush ; while in others they are thin and flat, with a cutting 

 edge like the incisor teeth in the human subject. Some 

 fishes that are without teeth in the mouth, have them in the 

 throat ; this is particularly the case in the Carp, and the 

 allied species in the family of the Cyprinida generally. In 

 this family the pharynx is provided with five pair of branchial 

 arches, the four most anterior of which support the four rows 

 of gills ; the fifth pair, remarkable for the strength of the 

 bone, support powerful teeth. The woodcut here introduced 



