APPENDIX. 



533 



there are only five or six in each. The teeth are 

 not divisible into different classes, as in quadrupeds, 

 but are all pointed teeth, and are commonly a 

 good deal similar. Each tooth is a double cone, 

 one point being fastened into the gum, the other 

 projecting: they are however not all of exactly 

 this shape. In some species of Porpoise the fang 

 is flattened, and thin at its extremity : in the 

 Spermaceti Whale the body of the tooth is a little 

 curved towards the back part of the mouth ; as is 

 also the case with some others. The teeth are 

 composed of animal substance and earth, similar 

 to the bony part of the teeth in quadrupeds. 



It would appear that these animals do not shed 

 their teeth, nor have they new ones formed similar 

 to the old, as is tlie cascA^dth most other quadrupeds, 

 and also with the Alligator. I have never been 

 able to detect young teeth under the roots of the 

 old ; and indeed the situation in which they are 

 formed makes it in some degree impossible, if 

 the young teeth follow the same rule in growing 

 with the original ones, as they probably do in 

 most animals. 



Some genera of this tribe have another mode of 

 catching their food, and retaining it till it is swal- 

 lowed ; which is by means of the substance called 

 Whalebone. Of this there are two kinds known : 

 one very large ; probably from the largest of all 

 Whales yet discovered ; the other from a smaller 

 species. The whalebone, which is placed on the 

 inside of the mouth, and attached to the upper jaw^ 



V. II. p. II. 35 



