244 Description of the Chlamyphorus truncatus. 



In the last named animal, the crowns of the teeth terminate 

 in two points, and, together with the bodies, are completely 

 enveloped in enamel ; they are so far separated from each 

 other, that when the jaws are closed, those of the lower jaw 

 pass between those of the upper ; furthermore, the teeth are 

 proportionally much shorter, neither sinking so deep into the 

 jaw, nor rising so high above the alveoli. The whole form 

 of the head, and of the jaws, particularly the inferior, will ad- 

 mit of no comparison in the two animals ; lateral motion being 

 almost entirely forbidden in the armadillo, and the greatest 

 freedom in this respect existing in the new genus : in which, 

 the condyloid extends above the coronoid process. 



The teeth in structure are most nearly allied to those of the 

 sloth, (Bradypus tridactylus, Lin.) that is to say, they consist 

 of a simple cylinder of bone, surrounded with enamel, except 

 the crowns, which are destitute of enamel in the centre ; the 

 roots, (or rather that portion buried in the jaw) of both these 

 animals, are hollow. In these particulars, together with the 

 short process descending from the zygomatic arch, which has 

 been alluded to before, as well as in the form of the fore-claws, 

 there is considerable analogy j but in all other points of orga- 

 nization, these two genera are most widely separated. 



As far as the nature of the subject will admit, I have now 

 gone through with the detail of the organization of this most 

 singular quadruped. During the investigation, I have had 

 frequent occasion to admire those laws of co-existence which 

 regulate the structure of organized beings ; Nature, true to 

 herself in this as in all other instances, has pursued an unde- 

 viating course. We have been presented in the subject before 

 us with a new form : an animal combining in its external con- 

 figuration a mechanical arrangement of parts which charac- 

 terises, respectively, the armadillo, the sloth, and the mole ; 

 constituting in themselves, individually and separately, of all 

 other quadrupeds, those which offer the most remarkable ana- 

 tomical characters. Pursuing the investigation step by step, 



