Io6 Bulletin American Museum of Natural History. [Vol. X, 



moderate length, with slightly overhanging nasals, much as in 

 Poebrothcrium tuilso/ii. The premaxill^e are relatively broad and 

 extend upwards and backwards to articulate with the nasals. 

 The orbit is not enclosed by bone posteriorly, but exhibits a 

 marked tendency towards that peculiar roofing so highly charac- 

 teristic of Poebrothcrium and the later Tylopoda. In advance of 

 this bony shelf is seen a faint though distinct indication of the 

 supraorbital notch, so constant a feature of the cameloid skull. 

 The lower jaws may be described as long and slender, with a 

 considerably elongated symphysis. 



The superior incisors are relatively small, of a more or less 

 conical form, and directed downwards. The premaxillae were 

 apparently not in contact in the median line. The superior 

 canine is but little larger than the outer incisor, of a more or less 

 hook-shaped appearance, and provided with a distinct sulcus upon 

 the outer portion of the crown as in Pocbrot/ieriu/n unlsoni. The 

 first premolar follows after a very short interval and, like the 

 second, is a simple two-rooted cutting tooth. The third premo- 

 lar has a faint internal cingular ledge, while the fourth, as already 

 mentioned, is provided with single external and internal crescents. 

 The molars are much worn, and do not show clearly whether or 

 not intermediate tubercles were present, but I think it may be 

 safely assumed, from the general appearance of the crown, that 

 they were absent. In the second and third molars, between the 

 internal crescents, is to be seen a small styliform cingular cusp 

 which is entirely absent, so far as I can determine, in Pocbro- 

 therium. 



In the lower jaw the incisors are of a more spatulate form and 

 more procumbent in position. As in the upper jaw, the canine is 



slightly larger than the 



„,3 m.t m.l p.4 p.3 p2 P< . . 



^^^^j^,pw~ -^^ _ \ ''^ outer incisor, but of a 



'ifiSfci^Q. jT^Jy^.^^-S^ ':^'^*-^'^'** very marked incisiform 



' pattern. After a very short 



pI^J;^. ^''°"" '■'" °^ '"""■ '""' °^ ^'rofy/oMs interval or diastema, is 



placed the first premolar, 

 a two-rooted tooth whose crown closely resembles that of the 

 canine, the two teeth being about equal in size. 'I'he second and 

 third premolars have elongated secant crowns like the Tragulines. 



