CREODONTA. 
109 
Bears. The zygoma and glenoid cavity are similar in size and other fea¬ 
tures to those of the Jaguar, but are much thicker and more robust in the 
Oxycena. Especially is the brain-case smaller and narrower, while the supe¬ 
rior osseous walls are much thicker, and the sagittal crest more elevated 
than in the Jaguar. The frontal region is concave in transverse section in 
the OxycBna^ convex in the Jaguar. 
STYPOLOPHUS, Cope. 
Slypolophns, Cope, Second Account New Vertebrata Bridger Eocene (Paleontological 
Bulletin No. 2), p. 1, Aug. 3, 1872; Proc. Amer. Philos. Soc., 1872, p. 4G6; 
Ann. Kept. U. S. Geol. Surv. Terrs., 1872, p. 659. 
fPrototomus, Cope, Report Vert. Foss. New Mexico, 1874, p. 13; Id. Ann. Report U. 
S. Geog. Survs. W. of 100th M., 1874, p. 125; System. Cat. Vert. Eocene New 
Mexico, U. S. Geog. Survs. W. of lOOth M., 1875, p. 9. 
Molars seven below, i. e., four premolars and three true molars, and 
probably the same number above. Inferior true molars consisting of three 
elevated cusps in front, and a low horizontally-expanded heel behind; the 
external cusp largest, the internal smallest, and the anterior intermediate, 
forming with the external a short sectorial blade. The inferior premolars, 
two-rooted (the first only seen in S. Mans) ; the crown consisting of a com¬ 
pressed cusp and short trenchant heel. Of the superior molars, the last is 
narrow, transverse, and with a blade-like crown. The two preceding have 
crowns forming right-angled triangles in horizontal section, the right angle 
being the antero-external. The antero-posterior cutting-edge consists of two 
cusps in the middle, and a short blade at the posterior angle of the crown. 
The internal angle supports a cusp. The last premolar has a trilobate sec¬ 
tion at the base, and supports a median subconic cusp, a short posterior 
blade, and an internal tubercle. The second premolar is compressed, with¬ 
out internal heel, and with a rudimental posterior one. The first preniolar 
is two-rooted in S. Mans. 
The species of /Stypolophus of which I obtained the best preserved 
remains is the S. viverrinus, an animal about the size of the domestic cat. 
Its mandibular bones and teeth are unknown, but I have derived from it the 
characters of the dentition of the maxillary bone, as above stated. The 
maxillary teeth of the S. muUicuspis are similar in generic characters, and 
of this species I know almost the entire dentition of the lower jaw. 
The posterior part of the cranium of S. viverrinus displays a low sagittal 
