170 THE MAMMALIA OF THE DEEP RIVER BEDS. 



Measurements. 



M. 



Length of premolar-molar series 079 



Length of premolar series 037 



P. 2, length 013 



P. 3, length 013 



P. 4, length 011 



Length of molar series 043 



M. 1, length 014 



M. 1, width 013 



St. 2, length 010 



M. 2, width 015 



M. 3, length 017 



M . 3, width 016 



2K B. — It will be observed that the length of the molar series is less than the sum of the lengths of the 

 individual teeth. This is due to the slight overlapping of the successive molars. 



The general aspect of the skull (PI. VT, Fig. 48) is quite similar to that of An- 

 tilocapra, though there are many important differences, which, as would naturally be 

 expected, are in the direction of more primitive conditions. The cranium is very 

 long and the face relatively short, as compared with that of most recent ruminants, 

 though long in proportion to the more ancient forms of the group. In correspond- 

 ence with this, the orbit is placed quite far forward, its anterior rim extending almost 

 to a line above m. 2 , and the zygomatic arch is decidedly longer than in the prong- 

 buck. The upper contour of the skull is almost straight, there being hardly any 

 descent at the forehead and little arching of the cranium. In some respects the 

 skull of Bla&tomeryx is more modernized than that of existing hornless deer, such as 

 Hydropotes and Mosclms, especially in the backward shifting of the orbit. In Hy- 

 drojiotes the orbit is almost entirely over the molars and in Mosclms its front border 

 extends nearly as far as the posterior border of m. 1 . In both genera, and especially 

 in Moschus, the orbit is raised much higher above the molar alveolus than in Blasto- 

 meryx. On the other hand, the recent genera have a proportionately shorter and more 

 rounded and capacious cranium, the upper contour of which is much more decidedly 

 arched from before backward, and the occiput is lower and without wing-like exten- 

 sions of the parietals. The paroccipital processes are not advanced in front of the 

 occipital condyles ; the zygomatic arch is much shorter and the glenoid cavity more 

 elevated above the plane of the molars, indicating a higher ascending ramus of the 

 mandible. 



The specimens do not indicate that in Blastomeryx the face was bent down the 

 basicranial axis, as in the recent Cavicornia and some other artiodactyls, but appears 

 rather to have been in the same line with it. The occiput is very broad at the base; 



