206 Annals of the Carnegie Museum. 



The lumbar vertebrae, six in number, are very well represented. 

 Besides being more delicate in their proportions, they have broader 

 and more depressed centra, more nearly like those of Merycoidodon 

 culhertsoni and the zygapophyses are less perfectly rounded than in 

 P. carrikeri. The first sacral vertebra has a much broader and more 

 depressed centrum, and the zygapophyses are wider apart than in P. 

 carrikeri, while the pleurapophyses indicate that the vertebra supported 

 the pelvis in a similar manner. The robust neural spine is isolated 

 from the succeeding sacrals as in P. carrikeri, but has a greater trans- 

 verse diameter. 



There are no caudal vertebrae of this species in our material. 



M EASUREMENTS. 



Mm. 



Fourth cervical, antero-posterior diameter of centrum 28 



Fourth cervical, transverse diameter of centrum, posteriorly 31 



Fourth cervical, vertical diameter of centrum, posteriorly 24 



Fourth cervical, greatest height including spine, approximately 50 



Second ? dorsal, antero-posterior diameter of centrum 28 



Second ? dorsal, transverse diameter including capitular facets for 



the ribs, posterior aspect 35 



Second ? dorsal, vertical diameter of centrum, posteriorly 18 



Fourteenth ? dorsal, antero-posterior diameter of centrum 35 



Fourteenth ? dorsal, transverse diameter of centrum 27 



Fourteenth ? dorsal, vertical diameter of centrum, posteriorly 18 



Fourteenth ? dorsal, height including spine 68 



Lumbar region, greatest length when placed in position 265 



Fourth lumbar, greatest transverse diameter including transverse 



processes 120 



Fourth lumbar, transverse diameter of centrum posteriorly 33 



Fourth lumbar, vertical diameter of centrum posteriorly 20 



Fourth lumbar, antero-posterior diameter of centrum 40 



Fourth lumbar, greatest height including neural spine 62 



Sixth lumbar, greatest transverse diameter including transverse pro- 

 cesses 124 



Sixth lumbar, transverse diameter of centrum, posteriorly 40 



Sixth lumbar, vertical diameter of centrum, posteriorly 17 



Sixth lumbar, antero-posterior diameter of centrum 35 



THE RIBS. 

 There are only a few fragments of ribs belonging to the type, which 

 are quite similar to those in P. carrikeri, and need not be described. 

 There are no sternebrae with the type or with any of the material which 

 is referred to this species. 



