HOMOLOGIES OF TEETH. 369 



termed c sectorials,' or ( molaires carnassieres.' Teeth of an 

 elongated conical form, projecting considerably beyond the rest, 

 and of uninterrupted growth, are called ' tusks ; ' such, for example, 

 are the incisors of the elephant, narwhal, dinotherium, and 

 dugong, the canines of the boar, walrus, and hippopotamus. The 

 long and large incisors of the rodents have been termed, from 

 the shape and structure of their cutting edge, scalpriform teeth, 

 chisel teeth, ( dentes scalprarii.' The lower incisors of the colugos 

 ( Galeopithecus), with the crown deeply notched like a comb, are 

 termed e dentes pectinati.' The canines of the baboons, which 

 are deeply grooved in front like the poison-fangs of some snakes, 

 are ' dentes canaliculati.' The compressed crowns of the teeth of 

 short-clawed seals (Stenorhynchus) and of the extinct Zeuglodon, 

 being divided into points like a saw, are ' dentes serrati,' &c. But 

 a true knowledge of nature, a right appreciation of what is 

 essential in her phenomena, tends to explode needless terms of 

 art invented for unimportant varieties, and to establish those 

 names that are the signs of true species of things. 



As most zoologists have adopted the Cuvierian system of 

 nomenclature and homology of the teeth in Mammalia, it may 

 not be superfluous to explain what is objectionable in that 

 system. In it the molar series of teeth, or those that follow the 

 canines, are divided, according to their form, into three kinds, 

 ' false molars,' i carnassials,' and { tubercular molars,' and the 

 generic dental characters of the Mammalia are formulised ac- 

 cording to this system. Thus, the genus Felis has — ( fausses 

 molaires' -§-:-§-, e carnassieres ' ^:^, e tuberculeuses ' ^:^ = f. This 

 seems a natural way of expressing the homotypal teeth, or the 

 answerable teeth in the upper and lower jaws. But to illustrate 

 its error, the subjoined diagram, fig. 293, is appended, in which 

 the dental system of the Cat-tribe {Felis v.) is associated with 

 that of other Mammals, and in which the line marked 6 Cuvier ' 

 intersects the teeth in each jaw, called * carnassieres,' those 

 anterior to them being the teeth called ' fausses molaires ; ' those 

 behind — a single tooth in the upper jaw of Felis — being the 

 I tuberculeuses.' In this genus the tooth, p 4, above chiefly plays 

 upon the tooth, m l, below, which has a similar sectorial or car- 

 nassial modification of form ; they fit, indeed, almost as Cuvier 

 describes, like the blades of a pair of scissors. The two teeth in 

 advance of the carnassial in the upper jaw, p 3, p 2, in like manner 

 are opposed to the same number of c fausses molaires ' in the 

 under jaw, and the canine, c, above plays upon the canine below : 



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