257 



The molars sliow no cliaracteristic differences t'roni tliose of the llama and 

 eamel. The narro\\' told seen projecting outwardly in advance of the antero- 

 external lobe of the last molar, and in a less degree in the second molar, in 

 the llama, is nearly obsolete in the fossil. 



The premolar presents some difference from the corresponding tooth *in 

 the llama. The crown is thickest, and is romided behind, and it narrows 

 lbr\\ard to the anterior subacute border, which is convex longitudinally, and 

 is thickened toward the bottom. The outer side is not impressed at the back 

 part, as in the llama, and is feebly impressed at the fore and upper part. The 

 inner side also is but moderately impressed along the middle, compared with 

 its condition in the llama. A deep enameled pit occupies the inner back part 

 of the crown, penetrating from the triturating surface, as in the latter. The 

 pit opens backward for a considerable portion of its depth, and is closed in 

 this position by apposition with the succeeding tooth. 



The measurements of the teeth, in comparison with those of the camel 

 and llama, are as follows : 



Fourtfi premolar: 



* Breadth of crovcu where greatest 



* Width of crown where greatest. . 

 Length of crown to origin of fangs. 



■ First molar : 

 Breadth of triturating surface. 

 Width of triturating surface . . 

 Length of crown 



Second molar: 

 Breadth of triturating surface. . 

 Width of triturating surface . . . 

 Width of crown where greatest. 

 Length of crown 



Third molar : 

 Breadth of crown where greatest. 

 Width of crown where greatest . . . 

 Length of crown 



Aucheuia 

 hesterna. 



Lilies. 



13 



G 



20 



20 



lOi 



20" 



20 

 10 



ai 



10 



41 



Aucbonia 

 lauia. 



Camel. 



Lines. 



•J.-i 



Lilies. 



12 



* For brevity I bave iised breadtb for tbo antero-posterior diameter, and width for tlio trausverso 



diameter. 



33 cf 



