HY ZNODONTID &. oD 
specimen is referred to the present genus on the authority 
of Bravard. Bravard Collection. Purchased, 1852. 
281634. Three lower premolars’ of small size, not improbably 
belonging to a small race of the present species; from the 
Upper Eocene of Vaucluse. 
Bravard Collection. Purchased, 1852. 
28154. Cast of a portion of the right ramus of the mandible, showing 
the last three premolars: the original is from the Upper 
Kocene of Vaucluse. Bravard Collection. Purchased, 1852. 
M.1719. Fragment of the left ramus of the mandible of a large- 
sized individual, containing the two last molars; and a 
fragment of the anterior part of a ramus with two worn 
teeth; from the Upper Eocene of Bach. Purchased, 1884. 
Genus ORY AENA, Cope’. 
This genus is apparently distinguished from Pterodon merely by 
the absence of the third molars in both jaws, and by the diminu- 
tion in the number of the incisors. Since one species of Pterodon 
(P. buncisivus) has only two pairs of incisors in the upper jaw, and 
' possibly only the same number in the mandible, there is a transition 
in this respect towards the present genus; and as the only other 
distinction is the absence of the last true molars, the writer is 
strongly inclined to think that Oxyena might be merged in Pterodon. 
The following formula’ represents the range of variation in the 
number of teeth of Oxycena, viz. I. os C. = Pm. = M. 3. 
Oxyzena galliz, Filhol*. 
Dentition :—I. 2, C.;, Pm. 4, M. 3. Filhol founded this species 
on a fragment of the maxilla in which the incisors were not shown. 
He was not, therefore, aware that these teeth were only two in 
number, in place of three, as in the American species. 
Hab. France. 
1 Entered in the Museum Register as P. aymardi, Bravard, MS. 
2 Report U.S. Geogr. Surv. W. of 100th Meridian,1874, p. 11. Vert. Foss. New 
Mexico. 
3 In his latest notice (Amer. Nat. 1884, p. 480) Cope gives the number of 
cheek-teeth as Pm. #, M. 3. The figure of the upper dentition given on the 
opposite page of his memoir shows, however, that this is incorrect. 
4 Ann. Soe. Sci. Phys. Nat. Toulouse, 1882, p. 34. 
D2 
