XIV 



INTRODUCTION. 



slippery prey is possessed by the Common Trout ! the vomer, palantines, intermaxillary, 

 maxillary, the mandible, and the tong-ue are all furnished with sharp conical teeth. Some 

 fish are entirely destitute of teeth in the mouth, others possess them in a very rudimentary 

 form. In the family of the Cyprinidcc, as the Carp, Tench, Roach, etc., the mouth is utterly 

 toothless, hence these fishes are popularly designated by anglers as "leather-mouthed" fishes; 

 but he would make a very great mistake who would assert that these fish are altogether 

 devoid of a dental apparatus. The teeth of the Cyprinidce are situated in the throat, on the 

 pharyngeal bones ; though formed on one general type these bones and teeth present 

 differences of form in different species, and this difference of form often possesses high value 

 in the determination of closely allied species or of hybrids. I have dissected out these 

 phar}'ngeal teeth from all the species of our CyprinidcE, figures of some of which are given 

 on page xvi. Let us notice the form and position of the dental apparatus in one of these 

 fishes, and from thence deduce the functions thereof. 



•hi li ^-itET *».■ p — ^^ 



Dental apparatus of Tench. 



The figure represents the dental apparatus of the Common Tench ; a Is the roof of the 

 mouth, b is the oesophagus, <: is a hardened and dilated projection from the basilar bone of 

 the cranium ; at d, d are seen the pharyngeal teeth. By means of strong muscles these 



Portion of alimentary canal of Salmon. 

 it. cardiiu h, pylorus. d, duodeiiiuli, or intestine, with numerous pyloric utccii at c. f, bilLMliK-t. 



teeth are worked upon the hardened body c, which forms a kind of anvil upon which the 



