42 Annals of the Carnegie Museum. 



County, Nebraska, in 1901. The type specimen consists of the 

 greater portion of the base of a skull with the lower jaws complete, 

 the limbs, the feet, and several cervical vertebrae. Only the skull 

 and lower jaws are free from the matrix, and these are illustrated. 

 The skull and lower jaws display characters which are entirely differ- 

 ent from any cameloid living or extinct known to the writer. Certain 

 cranial characters are quite suggestive of the Oligocene genus Hypi- 

 sodus, but the limb and foot structures are distinctly cameline. 



Principal Characters. 



r^, C-f, P 2 ~ , Mf . The more striking characters of the skull are 

 the position of the posterior nares with relation to the pterygoids. 

 The latter are located in the usual position, but they are very heavy 

 and are completely united at their origin, their extremities diverg- 

 ing downwardly and outwardly. The posterior nares are large, ovate 

 in outline, and are located well forward with the anterior border op- 

 posite the posterior part of Mi. This is well shown in the illustra- 

 tions. The tympanic bulla is of moderately large size ; it is well co- 

 ossified with the paroccipital process as in the camels generally. The 

 basicranial axis is strongly angled. The occipital condyles are quite 

 large and there are large accessory facets on the basioccipital. The 

 occiput is rather low. The lambdoidal crests are broken off superi- 

 orly, but enough is preserved to show that they are of considerable 

 prominence. There is no sagittal crest. The brain cavity is large 

 and the frontals have a great transverse expansion between the post- 

 orbital processes, which give to the orbit an oblique outward position. 

 The alveolar portion of the maxillary bone is very high for the ac- 

 commodation of the extremely hypsodont teeth, the crowns of which, 

 however, emerge but little below the alveolar border. The infraor- 

 bital foramen is above Mi. Anterior to P^ the skull is unknown. 



Pi is small ; it has a simple crown and two roots. The ectoloph 

 of Pi is smooth and nearly straight antero-posteriorly ; there is, on 

 the antero-external angle, a well developed vertical rib ; the internal 

 border is evenly rounded from before backward. The molars, espe- 

 cially the second and third, are of great antero-posterior diameter, 

 while transversely they are much compressed. The vertical ribs on 

 the antero-external angle of M^ and M^ are prominent ; otherwise 

 the external surfaces of the teeth are smooth. The intercrescentic 

 cavities of the second and third molars are large and deep. The pos- 



