450 Annals of ihe Carnecie Museum. 



cidedly hemispherical and the whole body of the centrum anteriorly 

 has a decurved position resulting in a greatly curved keel. Posteriorly 

 this vertebra is restored and the characters in this region are conjec- 

 tural. The restored parts are indicated in the illustrations by broken 

 lines. The anterior portion of the neural spine is preserved as it was 

 found in position in the rock and indicates a high laterally compressed 

 plate of bone similar to that of the recent camel and much unlike the 

 low heavy spine of the llama. The anterior zygapophyses are greatly 

 expanded, and the transverse processes are heavy and in general char- 

 acter resemble those of the living forms. 



Cervical vertebrae are rare among the Loup Fork camel remains so 

 far obtained, and some disappointment is therefore met with in a com- 

 parative study of them. When more complete material of the differ- 

 ent genera and species are discovered we shall undoubtedly be able to 

 determine whether or not the axis, es in Ca/iicli/s, is the longest ver- 

 tebra in the cervical series in any of the Loup Fork forms, or, if they 

 all, as in the llama, had the third and fourth cervical the longest. 

 On the whole, the structure in the cervical region of O. lougipes is far 

 more similar to that of the llama than to that of the recent camel. 

 The strong downward curve of the posterior cervicals which brings 

 the cranium more nearly on a level with the vertebral column in 

 Ca>/ielus seems to have been less apparent in O. lo/igipes. The latter 

 genus probably carried the head higher than the former. 



The Dorsa/s. — There are six dorsal vertebra represented in the 

 type specimen. Their relative positions as determined are the first, 

 fifth, sixth, seventh, ninth, and tenth, assuming that there were twelve 

 dorsals, which was the probable number. 



The First Dorsal. — The centrum of the first dorsal is approxi- 

 mately 1 8 mm. shorter than that of the last cervical, and also less 

 opisthocoelous. Inferiorly the centrum presents a faintly marked 

 median keel with strong lateral ridges. Between the lateral ridges 

 and the capitular facet is a deep pit or groove, which is also present 

 on this vertebra in recent forms. The neural spine is high, laterally 

 compressed, and comparatively broader than that in the camel and 

 the llama. The prezygapophysis and the tubercular facet together 

 form a heavy transverse process. The prezygapophyses are greatly 

 expanded and are placed low down, giving a depressed appearance to 

 the vertebra. The postzygapophysial facets of opposite sides are 

 confluent. In the camel and the llama there is a decided groove 

 separating the two facets. 



