1883.] 557 [Cope. 



The superior molars are more nearly quadrate than in the other species 

 of the genus, owing to the better development of the posterior internal 

 tubercle, which is, however, as in the others, a mere thickening of the 

 posterior cingulum. It is wanting from the last superior molar. The 

 cusps on the true molars are as in the M. ferox, small, and not large and 

 closely placed as in M. protogonioides. The intermediate ones are nearly 

 obsolete. The crowns are all entirely surrounded by a cingulum. The 

 entire enamel surfaces wrinkled so as to be rugose, although the teeth are 

 those of an adult and well used. The second superior molar is larger than 

 the first, exceeding it in the transverse rather than the fore-and-aft diame- 

 ter. The third is the smallest, and is of oval form with obliquely truncate 

 external face. It is less reduced than in the M. turgidus. 



The fourth premolar consists of a strong compressed-conic cusp with 

 three basal cusps of small size, viz., an anterior, a posterior, and an in- 

 ternal. The last is the larger, though small, is formed like a heel, and is 

 connected with the others by a cingulum. No external cingulum. 



Measurements. M. 



Length of last four molars 036 



Diameters P-m. iv { anteroposterior .010 



<- transverse 008 



" M i I an t ero P°sterior .010 



I transverse 010 



" M i'i -T anteroposterior 008 



I transverse 011 



From the Upper Puerco beds. 



Pantolambda bathmodon Cope, American Naturalist, 1882, p. 418. 



In describing this genus and species, I remarked, loc. cit., that they 

 were "founded on a mandibular ramus, which supports the first true 

 molar, and the last two premolars. The characters of these teeth remark- 

 ably resemble those of Goryphodon. * * * It will be for additional 

 material to demonstrate whether this genus belongs to the Airiblypoda or 

 Perissodactyla. ' ' 



A considerable part of the skeleton of this species having been recently 

 sent me by Mr. D. Baldwin, I am able to throw much light on the affini- 

 ties of this curious genus. 



In the first place, the phalanges (not ungual), show that the genus is 

 ungulate. Secondly, the astragalus has a large distal facet for the cuboid 

 bone. This proves that the genus cannot be referred to the Taxeopod 

 order. The question as to whether it belongs to the Amblypoda or the 

 Diplarthra would be decided by the carpus, but that part is unfortunately 

 not preserved, and I have to rely on empirical indications for a provisional 

 determination. Apart from the astragalus, the characters are those of the 

 Condylarthra rather than of the Perissodactyla, and it is therefore to be 

 supposed that the carpus has also the characters of that order. This would 



