EDENTATA OF THE SANTA CRUZ BEDS. 30! 



different from those of Hapalops, being very much lower, narrower and 

 more inclined, each one overhanging the vertebra behind it, and much 

 thickened at the free end ; the transverse processes also are much shorter 

 than in the last named genus and are more elevated, projecting obliquely 

 upward ; except on the first lumbar, they are very broad and are some- 

 what thickened at the distal end. The accessory zygapophyses are of the 

 type common to all the family and the metapophyses are small. 



The sacrum consists of five vertebrae and its only noteworthy feature is 

 the fact that the ridge formed by the coalesced neural spines is very low. 



The pelvis is very similar to that of Hapalops, with a few minor dif- 

 ferences. Thus, the ilium has a somewhat more concave gluteal surface, 

 which presents more obliquely and less dorsally ; the sacro-sciatic foramen 

 is larger, especially in the dorso-ventral diameter ; the pubis and descend- 

 ing process of the ischium are longer, making the posterior pelvic opening 

 higher and narrower, and the obturator foramen is larger and of a more 



oval shape. 



MEASUREMENTS. 



Last thoracic, length of centrum 018 Third lumbar, height of neural spine. . . .030 



" " width of anterior face . . . .022 " " width of spine at tip 020 



width over transverse Fifth lumbar, length of centrum 02 1 



processes 040 " " width of anterior face 026 



height of neural spine ... .028 " width over tranverse 



width of spine at tip 013 processes 070 



Lumbar region, length 144 " height of neural spine. . . .027 



First lumbar, length of centrum 018 " " width of spine at tip 021 



width of anterior face 023 Sacrum, length 105 



" width over transverse pro- First sacral, width of anterior face 030 



cesses 06 1 Last sacral, width of posterior face 025 



height of neural spine 030 Pelvis, length 204 



width of spine at tip 016 " greatest width 208 



Third lumbar, length of centrum 022 Ilium, length 1 28 



" width of anterior face ... .025 " greatest width 079 



" width over transverse Ischium, length 076 



processes 052 Posterior pelvic opening, width 08 1 



In the Ameghino collection is a well preserved fore-leg and foot ; the 

 bones resemble those of Hapalops, with certain minor differences. The 

 humerus is of nearly the same length as that of H. elongatus, but some- 

 what heavier, and the deltoid area is distinctly less prominent, while the 

 internal epicondyle and supinator ridge are better developed. The radius 

 is so like that of the latter as to require no description. 



