78 , ME. C. W. ANDREWS ON THE SKULL AND 



Vertebrae. 



Of the vertebra, other than those forming the synsacrum, only three are preserved in 

 this specimen. Of these one is the last free dorsal and the others anterior free candals. 

 The last dorsal has a short centrum, terminated by the usual saddle-shaped articular 

 surfaces, of about equal height and breadth. The ventral portion of the anterior two- 

 thirds of the centrum is pinched up to form a prominent haemal ridge, the summit of 

 which has been broken away. Laterally the anterior end of the centrum is widened 

 out by stout parapophysial prominences, bearing each an oval cup for the head of the 

 rib. The diapophysis is broken away : immediately beneath its base is a large 

 pneumatic fossa, and another occurs on the side of the centrum. The zygapophyses 

 are of the usual form ; the neural spine is very massive, and has its anterior and 

 posterior surfaces roughened for ligamentous union with the spine in front and behind 

 it : its upper portion is broken away. 



The caudal vertebra (Plate XVII. fig. 7) have centra about as long as their anterior 

 face is wide, slightly constricted in the middle, and bearing towards their hinder end a 

 pair of strong, backwardly-directed transverse processes, only the bases of which remain. 

 The anterior articular face is wider than high, the posterior about equal in the two 

 directions ; the anterior surface is slightly concave, the posterior convex, but with a 

 median pit, which probably marks the primitive position of the notochord. The neural 

 arch does not extend quite to the hinder end of the centrum, and the neural spine is 

 greatly thickened at its upper end, which forms a flat bilobate surface, which was 

 evidently connected with the vertebrae before and behind by tendons, probably more 

 or less ossified. 



The Femur. (Plate XVII. fig. 8.) 



The head of the femur rises to a marked degree above the level of the trochanter, 

 the upper portion of the elevation being formed by a large blunt-pointed process, which 

 partly divides the deep pit for the ligamenturn teres into two parts. Ventrally also the 

 articular surface is divided by a shallow groove into an anterior and a posterior lobe, so 

 that when looked at from the inner side the head appears to be imperfectly trilobate. 

 The neck is much hollowed out on its ventral surface, and the head is clearly peduncu- 

 late. The articular surface of the trochanter is continuous with that of the head, 

 at least posteriorly. 



On the anterior, and particularly on the outer, face of the trochanter are a 

 number of extremely distinct impressions of muscle-insertions. The shaft is as nearly 

 as possible straight, there being only a slight forward convexity in its lower portion. 

 In the middle it is cylindrical in section, but just above the condyles it is somewhat 

 flattened from before backward. The postero-internal border is defined by an 

 extremely conspicuous linea aspera, which, as Ameghino remarks, is a veritable 

 pro]ecting lamina of bone. It runs from end to end of the shaft, terminating below 

 in the upper angle of the inner condyle. The anterior face of the shaft is likewise 



