308 PROCEEDINGS OP THE ACADEMY OF [1892. 



DELTATHERIUMi Cope. 

 Syn. Lipodedes- Cope. 



II Cr Pf Ma. This genus has already become quite specialized 

 through the loss of one premolar in each jaw and the complication 

 ofp*. 1^2, the most anterior premolar, is simple, compressed and 

 with cutting edges. 1% is more pyramidal in shape and is supported 

 by three fangs, though it has no deuterocone, which is well developed 

 on P4. The molars are triangular in shape, with only a slightly 

 thickened cingulum representing the hypocone; rnj is the largest 

 and "la the smallest of the series. The para- and metacones are some- 

 what a[>proximated and are moved mesially from the outer edge of 

 the crown ; from the metacone is given off a short, curved, tren- 

 chant crest which runs to the postero-external angle of the crown, 

 and at the antero-external angle there is a small parastyle ; the 

 conules are rudimentary or absent. In ^3 the metacone is rudi- 

 mentary and has no posterior crest. The anterior lower premolars 

 are simple, but lu has become almost molariform, with well devel- 

 oped trigonid formed by the addition of the para- and deuteroconids, 

 but the heel is rudimentary. The lower molars are very primitive; 

 the trigonid retains all the elements and the meta- and paraconids 

 are on the same fore and aft line, so that there is only a beginning 

 of a shearing blade; the talon has become trenchant through loss of 

 the entoconid. The skull has a very long and narrow cranium, with 

 cerebral fossa of small capacity ; the face is short and the orbits 

 placed far forward, much in advance of the very deep post-orbital 

 constriction ; the nasals and parietals do not lie in the same plane, 

 the profile of the skull rising somewhat at the forehead ; the sagittal 

 crest is very long and high ; the occiput is low and broad and the 

 occipital crest strongly developed. 



One species : D. fundaminls Cope, (Syn. Lipodectes penetrans 

 Cope). Puerco. 



SIN0PA3 LeiJy. 



Syn. Limnocyon^ Marsh, in part, Stypolophu^ Cope, Prototomus^ Cope, 



TriacoJoti^ Cope. 



In view of the imperfect condition of Leidy's type and the meagre 

 description which he gave of it, I have hesitated long in adopting 



lAmer. Naturalist, 1880, p. 338. 



2 Loc. cit. 1881, p. 1019. 



» Proc. AcaH. Nat. Sci., 1871, p. 115. 



* Am. Journ. Sci. 3rd Sen, Vol. IV, 1872, p. 126. 



5 Proc. Am. Phil. Soc, 1872, p. 446. 



"Rept. Vert. Foss. New Mexico, 1874, p. 13. 



' Proc. Am. Phil. Soc, 1872, p. 460- 



