204 Annals of the Carnegie Museum. 



Third Cervical Vertebra. — PI. XL, Figs. 2, 4. Besides the much 

 smaller proportionate size of the third cervical vertebra, when com- 

 pared with 0. longipes, there are other noticeable differences. The 

 anterior and posterior divisions of the transverse process are not con- 

 nected in a continuous ridge as in Oxydactylus longipes, Procamelus 

 elrodi Douglass, and also apparently in Alticamelus alius, but fade 

 away on the side of the centrum, indicating faint parallel ridges, with 

 the posterior division superior in position to the anterior division. 

 On the external faces of the prezygapophyses are prominent emi- 

 nences in the type under description, which are entirely absent or 

 poorly indicated in 0. longipes. The neural spine is not so high as 

 in the latter species, but it is heavier and the median antero-posterior 

 area has a transversely broad and rugous area for muscular attachment 

 (see Fig. 4. PI. XL). 



Fourth Cervical Vertebra. — PI. XL, Figs, i, 3. The fourth cervical 

 has the centrum very nearly as long as the one preceding it, but the 

 pre- and postzygapophyses are less overhanging. The anterior and 

 posterior divisions of the transverse processes are less separated as 

 parallel ridges, on the sides of the centrum, and the bone as a whole is 

 heavier; t:)therwise there is very little difference in the detailed struc- 

 ture of the two bones. In 0. longipes the centrum of the fourth cer- 

 vical vertebra is about 30 mm. longer than in the present species. 



Fifth Cervical Vertebra. — The fifth cervical vertebra is represented 

 only by the anterior portion. The zygapophyses are quite heavy, but 

 the anterior face of the centrum is no larger, nor is the anterior division 

 of the transverse process any heavier than in the corresponding bone of 

 0. longipes. 



Measurements. Mm. 



Atlas, greatest length 92 



Atlas, length of neural arch, superiorly 47 



Atlas, length of neural arch, inferiorly 47 



Atlas, transverse diameter of articulation for condyles 62 



Atlas, vertical diameter of articulation for condyles 37 



Atlas, vertical diameter of articulation for axis, including the neural 



arch 48 



Atlas, transverse diameter of articulation for axis 61 



Axis, greatest length 163 



Axis, length of centrum, including odontoid process 146 



Axis, transverse diameter of articulation for atlas, approximately. . 78 



Axis, transverse diameter of postzygapophyses 40 



