500 University of California Publications in Geology [Vol. 10 



ports a strong prezygapophysis. On the inner face of the latter a 

 large articulating surface is directed mainly to the inner side. 



Three of the caudal vertebrae have been determined as the fifth 

 to seventh inclusive (see figs. 18, 19 and 20; also 21a, 216). In this 

 series the centra become progressively less broad, as indicated by 

 the transverse diameter of the anterior face, and increase slightly in 

 length. The groove extending backward and upward from between 

 the anterior and posterior chevron facets of each side is well defined 

 by a crest which extends from the pedicle supporting the anterior 

 chevron facet to the base of the transverse process. This groove is 

 present also in caudal vertebrae of the Miocene genus Hapalops. The 

 anterior chevron facets are not nearly so far apart as in the second ( ? ) 

 caudal vertebra, and in the series from the fifth to seventh vertebra 

 inclusive they decrease in size. In the seventh these facets are quite 

 small as contrasted with the posterior facets, and are supported on 

 rather prominent pedicles. The posterior facets are large and ap- 

 proximate each other closely in the median line in the sixth vertebra. 

 In the seventh vertebra they are decidedly farther posterior to the 

 forward facets than are those in the fifth and sixth vertebrae. 



In the fifth caudal vertebra the outer third of the transverse 

 process is sharply bent downward. This is particularly well shown 

 on the right side of the specimen from Hawver Cave. The transverse 

 processes of the two succeeding vertebrae become progressively broader 

 anteroposteriorly and their outer portions are not bent downward so 

 decidedly as in the fifth vertebra. 



Measurements of Vertebrae 



No. No. No. No. No. 



21476 21477 21478 21479 21480 



Length of centrum a'50.7 mm. 50.4 50.1 50.2 51.4 



Depth of centrum across anterior 



face o47 50.8 48.4: 49.4 46.4 



Width of centrum across posterior 



face 75.7 67.8 63.8 57.3 



Depth of centrum across middle of 



posterior face 52.5 50.5 50.3 47 



Width across transverse processes .. o226 206.4 163.5 165.4 <zl52 



Greatest width across prezygapo- 



physes o96 91.8 72.4 a67 



Greatest width across postzygapo- 



physes a58 53 47.3 a45 



Height from ventral border of post- 

 erior face of centrum to top of 



neural spine all2 a92 85.2 a82 «77 



a, approximate. 



