600 THE PUEECO FATJfTA. 



A considerable part of the dentition of the mandible of this species was 

 found in the Big-Horn bad lands. This includes an incisor tooth, which is 

 quite characteristic, and renders it probable that the anterior parts of the 

 jaws differ considerably from those of other Uinatheriidce. The root is sub- 

 round. The crown resembles a good deal that of the species of Corypho- 

 dontidce. It is higher than wide and has a subacute apex. One edge of the 

 crown is convex, and the other concave. The external face is concave in 

 both directions, and has no ridges nor cingulum. The inner face is con- 

 cave longitudinally and convex transversely. The convexity is median 

 and has a longitudinal concavity on each side of it. No internal cingulum 

 except a trace at the base of the concave edge. The edges are obtuse even 

 when unworn, and the enamel is obsoletely rugulose. 



Measurements of yiicisor. 



I auteroposteiior 012 



Diameters of crown < transverse 020 



( vertical 020 



Diameters of root ^'^°*<'™P°^*''"°'" *^,J'^ 



< transverse 014 



This incisor (see Plate LVIII a. Fig. 7) is very different from the kind 

 seen in Loxolopliodon. Messrs. Scott, Spier, and Osborne have shown that 

 genus to have these teeth with compressed two-lobed crowns, a type un- 

 known elsewhere among Mammalia. 



TALIGRADA. 



Since the preceding pages defining the suborders of the Amblypoda 

 were printed, I have learned and described the characters of the genus 

 JPantolamhda^. These indicate the existence of a third suborder of the 

 Amblypoda, which I have called the Taligrada. 



In the first place, the phalanges (including ungual) show that the 

 genus is ungulate. Secondl}', the astragalus has a large distal facet for the 

 cuboid bone. This proves that the genus cannot be referred to the Taxeo- 

 pod 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 



'American Naturalist, 1883, April, p. 406 (March 151. 



