PETERSON: A REVISION OF THE ENTELODONTIDAi 53 
In the Carnegie Museum is a good portion of a skeleton with the vertebral 
column well represented, but without the skull or jaws (No. 1665, Carn. Mus. Cat. 
Vert. Foss.), collected by the writer in the Titanotheriwm beds on Sand Creek, Sioux 
County, Nebraska. This specimen has the sides of the walls of the neural arches 
perforated in a manner similar to that of the type of A. crasswm. The specimen per- 
tained to a somewhat larger individual than the type in the Yale Museum, but it is 
here referred to Archxotherium crassum. A skull and four cervical vertebrae (Carn. 
Mus. Cat. Vert. Foss. No. 142) which are referred to A. crasswm, were collected by 
Mr. J. B. Hatcher in 1900, near the base of the Titanotherium beds on Lance 
Creek, Converse County, Wyoming. The skull of this specimen is much depressed by 
crushing, but is of interest because it supplies characters which show a considerable 
range of individual variation in this species. While the skull is of about the same 
proportionate size as that of A. crasswm in the Yale Museum, it is seen that the 
dependent process of the jugal is of much smaller size and shorter, the superior 
border of the orbit is higher’ or more nearly even with the transverse face of the 
frontals, the antorbital foramen is slightly further forward, and the cingula of the 
teeth are more strongly developed than in the specimen in the Yale Museum. 
Archeotherium ingens (Leidy). 
Types: Symphysis of lower jaws without teeth, the crown of an inferior 
molar, and several mutilated canine teeth. 
Horizon: Oligocene (Upper Titanotherium beds’). 
Locality: Nebraska (White River?). 
Locality of Types: Unknown to the writer." 
The figures 8-11, which Professor Leidy gives on Pl. XX VII in “The Extinct 
Mammalian Fauna of Dakota and Nebraska,” seem to agree with his original 
description of “ Wntelodon ingens” (47, pp. 164-165) and are undoubtedly to be 
regarded as the types of that species, although Leidy does not make this clear. ‘The 
species was originally separated wholly on account of its greater size. On pages 
192-194 (Ext. Mam. Fauna) Leidy gives a list with measurements of specimens, 
which he regarded as pertaining to A. imgens, but with no adequate description. 
To Professor W. B. Scott of Princeton University we are indebted for an admirable 
Memoir (87, pp. 273-324), the descriptions in which are based on a very nearly 
complete skeleton (Princeton Museum Collection No. 10885) collected in the upper 
Titanotherium beds of South Dakota by the late Mr. J. B. Hatcher and regarded by 
10 Even when the crushing of the skull is taken into proper consideration this character is especially noticeable. 
11 Yn the Proc. Acad. Nat. Sci. Philad., Vol. VIII, p. 165, 1856, Professor Leidy states that the specimens were 
collected by Dr. Hayden for the St. Louis Academy of Sciences. 
