20 CONTENT SO FA BONE CAVE. 



The centra of the lumbar vertebrae are strongly constricted at the middle, and 

 they display an arterial foramen near the middle of each side; their inferior surface 

 is regularly convex, and without keel. One of the articular faces has a slight ten- 

 dency to convexity. Neural canal wide. The proximal extremity of the first sa- 

 cral centrum is plane, and not depressed nor concave. The inferior faces of the 

 sacral vertebrae are slightly concave in the anteroposterior direction. The cen- 

 trum of one of the canals is oblique in the vertical plane of one of its extremities. 

 Its inferior surface is strongly convex, the superior moderately so. The base of 

 the diapophysis is oblique. 



DIMENSIONS OF LUMBAR AND SACRAL VERTEBRAE, ETC. 



M. 

 Length centrum No. 1 ... ... .036 



Diameter anterior articular face 5 vertlcal 38 



(.transverse .... .038 



" posterior face j vertical ' 41 



(transverse . . . . .046 



Length centrum No. 2 ...... .045 



anterior articular face 



posterior articular face 



Diameter anterior articular face f vertlcal - 039 



(transverse . . .044 



(vertical . . . . .040 



(transverse .... .054 



Length three sacral centra . . . . . . .113 



" of first sacral centrum ..... .052 



Diameter of articular face of first sacral { vertlcal 



(transverss . . .048 



Length of third sacral centrum . . . .026 



Diameter of third sacral centrum in front I vcrtlcal 



(transverse . . .026 



Length of centrum of a caudal . . . . .022 



Diameter of articular face of a caudal \ vcrtlcal 



(transverse . . .024 



No scapula certainly referable to this species has been preserved. The proximal 

 and distal extremities of the humerus differ from those of the A. inundata in their 

 superior size. The supracondylar fossa is not perforate. The fossa of the great 

 trochanter of the femur is only excavated in the inferior half, its lower border being 

 opposite the middle of the neck of the femur. Its superior portion is the deepest, 

 and the fundus corresponds to a projection of the opposite border of the external 

 face. The external face of the femur is flat to as far below the little trochanter 

 as the length of the great one, when it passes by. a regular curve into (he posterior 

 face. The angular ridge bounding the anterior face continues further down. The 

 anterior face of the femur is well defined by lateral parallel ridge-angles, and main- 

 tains a nearly equal width from its middle to near the proximal extremity of the 

 great trochanter. Near the middle (where my specimens are broken off) it is 

 gently convex, but it soon becomes flat, and is slightly concave at the base of the 

 great trochanter. The extremity of the latter is a wide continuation of the exter- 

 nal face of the shaft, rising obliquely inwards. Its borders are roughened and at 

 some points overhang, furnishing points of muscular insertion. It projects beyond 



