17 



Antero-posterior diameter of orbit 048 



I'erpoiulicular diameter of orbit about .043 



It is possible that tliis skull may beloug to some species the in- 

 ferior dentition of wliicli lias already been described; but in the same 

 locality I have found two rami which I provisionally refer to the same 

 species. These rami are diffi'rent from anything with which I am 

 acquainted. It is possible that these two specimens are from distinct 

 species, but they are so nearly alike that I prefer to consider them 

 as one until other parts are found. 



Mandil)le. The specimen which I take as a low'er jaw type con- 

 sists of a horizontal ramus broken off a little back of the second 

 molar, with a third incisor, the first premolar, and the first molar 

 complete, and the larger part of the second molar, with parts of 

 alveoli of incisors 1 and 2. of the canine, and complete alveoli of the 

 third and fourth premolars, with a small portion of pi*emolar 4. 



The jaw is slender. The lower part of the anterior portion in 

 front of the angle of the chin, is nearly horizontal but slightly con- 

 cave to a point beloAv the third incisor. Here there is a rather abrupt 

 upward curve, but the exact shape of this portion is difficult to make 

 out as it is somewhat broken and displaced. The third incisor is rather 

 broad and thin, concave within, and convex on the outside. It is semi- 

 procumbent, as were also the first and second incisors. There is a short 

 diastema between the third incisor and the canine, which, judging 

 by the portion of the alveolus remaining, was not a very large tooth. 

 The distance between the canine and the first premolar is about 20 

 mm., and the distance from the first to the second premolar is about 

 the same. The first premolar is small and thin with sharp edges and 

 a long backward-curving root. The second premolar was small and 

 one-rooted. Molar one has a high crown. The foramen meniah is 

 near the angle of the chin, just in advance of premolar 1. There is an- 

 other foramen beneath premolar ?,. The jaw fits fairly well the skull 

 just described. 



MEASUREMENTS. 



M. 



Length of jaw from tliird incisor fanteridr edge) to molar .3.. .1!>2 



Canine to first premolar, about 020 



First premolar to second premolar 021 



Alveoli of premolars 2. ?. and 4 045 



Length of third incisor ; Oil 



Width of third incisor, transverse 006 



Height of third incisor 020 



