CONDYLARTHRA. 419 



somewhat compressed between the canine alveoli and the bases of the 

 malar bones. The orbits are rather small and are open posteriorly. There 

 is an obtuse postorbital angle of the frontal bone, and sharp temporal 

 angles originate from these and converge posteriorly, and probably form a 

 sagittal crest; but this part is broken off. The infraorbital foramen is 

 above the posterior part of the third superior premolar. The frontal bone 

 is convex downwards to the postfrontal angles, but is concave medially. 



Measurements. 

 No. 1. 



Length of posterior five superior molars 0226 



_. . .1 • J 1 < auteroposterior 0045 



Diameters third premolar^ . '^ „,„ 



I transverse 0040 



Diameters fourth premolar I '»°"'^°P°«**^"*^'- ^"^^ 



( transverse 0055 



Diameters first true molar ^^°*«"^°P°«t«^'°^ 0^45 



> ( transverse 0058 



Diameters third true molar J ••'°**'^°P°«t«"'"- ^^^ 



I transverse OOoo 



No. 2. 



Length of posterior five superior molars 0220 



Length from canine to M. iU inclusive 0340 



Long diameter base of crown superior canine 0050 



Width between postorbital angles 0260 



Length base of inferior P-m. ii 0045 



Length base of inferior P-m. iii 0070 



Width base of inferior P-m. iv 0040 



Diameters M.i I ^°t«'*'P°«*«"<"" ^^^ 



I transverse OUdO 



Diameters M.ii^''°'«^°P°«*«"<"" ^^° 



< transverse .OOdo 



Length M. iii 0052 



Depth ramus at P-m. iii 0100 



Depth ramus at M iii 0145 



No. 3. 



Length of ramus from canine to edge of angle 0760 



Depth ramus at M. iii 0155 



Elevation of condyle above base of ramus 0300 



Anteroposterior width base of coronoid 0220 



The compression and enlargement of the external anterior cusp of the 

 inferior true molars is a peculiar feature of this species. It is perhaps ho- 

 mologous with the crest which extends from this cusp to the anterior median 

 in the Anisonchus gillianus. It suggests a more or less carnivorous habit for 

 the species. 



From the upper Puerco beds of Northwestern New Mexico. 



