Merriam.1 New IcJlthjJOS(IUri<l . 261 



Measurements. 



Middle dorsal centrum, length 11 mm. 



" » » height *14.5 



Anterior caudal centrum, length 10 



" " " height 13 



The ribs associated with the dorsal vertebrae described above 

 have broadly forked heads, the two articular surfaces being sep- 

 arated by a strong notch (PI. 24, fig. 4). A prominent ridge 



begins behind the point of separation of the two heads and runs 

 along the upper portion of the anterior side of the shaft as in 

 Shastasaurus. A little farther back in the column the two heads 

 are still distinctly separated, but the notch between them is 

 much shallower. Numerous cross-sections of ribs show both the 

 circular section such as is obtained near the end and the con- 

 stricted section obtained in the doubly grooved middle or proximal 

 portion of the shaft in Shastasaurus. 



Posterior arch (PI. 24, fig. 3). — The entire pelvic arch lay 

 below the vertebral column, immediately in front of what are 

 recognized as the anterior caudal vertebra?. Although the girdle 

 is moved from its normal position with relation to the vertebral 

 column, the elements are in very nearly their natural positions 

 with relation to each other. The ilia are considerably longer 

 than the ischia and pubes, and are much more slender and 

 longer than in Shastasaurus perrini. The ischia are also nar- 

 rower than in *S'. perrini. In the extremely broad pubes the 

 obturator notch of Shastasaurus is represented by an obturator 

 foramen . 



Measurements. 



Ilium 



Length to broken distal end 29 mm. 



Ischium 



Greatest length 22 



Greatest width 14.5 



Pubis 



Greatest length 23.5 



Greatest width 22 



Posterior limbs (PI. 24, fig. 1). — Both of the posterior 

 extremities lie near the pelvic arch. The proximal portion of 

 each limb had been beautifully exposed by weathering, but 

 unfortunately the phalanges are missing. 



*Approxiinate. 



