A NEW FOSSIL PACHYDERM. 



273 



and posterior parts of the cranium the peculiar narrowness which 

 gives to the anterior portion such an extraordinary appearance. 

 The singular position of the lachrymal foramina, extei-nal to the 

 orbit, and anterior to the lachrymal tubercle, as well as the upward 

 aspect of that part of the bone (almost perpendicular to the exter- 

 nal face), will also be found worthy of remark. 



In the lower jaw we observe farther evidence of this great com- 

 pression, while the inferior expansion of the bone around the angle 

 is observed only in the hippopotamus among existing pachyder- 

 mata, and in that genus on a much less extensive scale. As the 

 posterior margin of the maxilla is somewhat concave, this expan- 

 sion must be considered as a much modified development of the 

 ferine type, in which the expansion is continued directly back- 

 wards. 



From an attentive study of the os cuboides and metatarsal, it 

 will be seen that Platygonus combines the characters of the Iso- 

 dadyle with those of the Anisodactyle Ungulata, retaining at the 

 same time the essential characters of the latter. It appears to have 

 had three well-developed toes, with a rudimentary external toe ; 

 the relation existing between the astragalian and calcaneal faces 

 of the cuboides is different from any that I can find described. 

 But being obliged to deduce these analogies from drawings and 

 descriptions, without reference to specimens, the observations must 

 necessarily be imperfect, and I am therefore unable to draw the 

 inferences which would become obvious to a student having access 

 to the great museums of Europe. 



The study of the bone of the antebrachium is more satisfactory : 

 the radius and ulna are firmly anchylosed throughout their whole 

 length, and the inferior surfaces resemble closely those of rumi- 

 nants, without being identical ; the two elevated lines separating 

 36 



