48 The American Naturalist. [January, 



Length of humerus 240 *' 



Width of distal end of humerus 73 " 



Length of tibia 237 " 



Width of proximal end of tibia 61" 



Width of distal end of tibia 41 " 



The relation of H. oecidentalis to Eusmilus dakotensis Hatcher, pub- 

 lished in the December Naturalist, is at once apparent. By com- 

 parison with the excellent figure by Mr. Weber, republished by per- 

 mission in the accompanying plate, it will be seen that H. oecidentalis 

 stands directly ancestral to E. dakotensis, the dentition agreeing very 

 strikingly in the characters emphasis ,1 by Mi. II itcher, but differing 

 in showing an and premolar and the presence of a 



heel on the sectorial. In Eusmilus bidentatus Filhol, the type of the 

 genus, the heel is present. 



Hoplophoneus insolens sp. nov. 

 The determination of the characters of H. oecidentalis makes it ob- 

 vious that the skeleton determined as such by Osborn and Wortman is 

 a new species. A complete skeleton (number 11,022) and a second 

 specimen with the most of the limb bones and a skull lacking the man- 

 dible (number 11,372), both in the Princeton Museum, enable me to 

 determine the skull of this species, a character which is lacking in the 

 American Museum specimen. The particularly close agreement in the 

 size of the skeletons makes either of them typical, consequently I give 

 the measurements already published in the American Museum Bulletin 

 along with measurements from the Priuceton specimen as indicative of 

 the size of the species. 



The skull of H. insolens is long and low, the postorbital constriction 

 very marked, sagittal crest slightly concave, the occiput overhanging 

 and concave from side to side, the posttympanic process is long and 

 massive approaching the postgleuoid process and being produced as far 

 inferiorly. The limb bones have stout shafts and relatively small ex- 

 Dentition : I»,Ci, Pm f, M {; the second upper premolar which 

 is variable in the genus usually being absent in this species. 



Length of skull, condyles to premaxillary border . 190 mm. 



Length of humerus 200 '* 



Length of ulna 212 " 



Length of radius ] 60 " 



Length of femur 250 " 



Length of tibia 188 »< 



Length of pelvis 210 " 



