162 Dr. Harlan on a new Genus of Edentata, 



the skull of our animal with that of the armadillo, {Dasypus 

 sexcinctus, Lin.) a few traits of similarity of typification are 

 visible : both these animals being equally destitute of incisor and 

 canine teeth in either jaw ; in both, a considerable space inter- 

 venes between the anterior margin of the os intermaxillare and 

 the commencement of the teeth; and in both the number of molar 

 teeth is the same, viz, eight on each side of both jaws — thirty-two 

 in all. Here all further analogy with the Dasypus is at an end. 



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

 two points, and, together with the bodies, are completely en- 

 veloped in enamel ; they are so far separated from each other, 

 that when the jaws are closed, those of the lower jaw pass be- 

 tween those of the upper ; furthermore, the teeth are proportion- 

 ally 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 admit 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 pro- 

 cess descending from the zygomatic arch, which has been alluded 

 to before, as well as in the form of the fore-claws, there is con- 

 siderable analogy; but in all other points of organization 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 occa- 

 sion 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 undeviating course. We 

 have been presented in the subject before us with a new form : 



