Mylodon harlani, from Rock Creek, Texas. 361 



moth. In the anterior ribs the two facets lie in a plane nearly 

 perpendicular to the long axis of the bone and are closely 

 approximated, whereas in the more posterior ribs the tuber- 

 cular facet lies at a level some distance below the capitular and 

 widely removed from it horizontally. 



The anterior rib of the left side has the following dimen- 

 sions : 



mm 



Distance over capitular and tubercular facets 70 



Capitular facet, ant.-post.* diameter 33*5 



" " transverse " ._ 23*5 



Thickness of mid-shaft 95 



Breadth " " 35 



This rib is quite sharply curved and its outer surface gives 

 evidence of abundant muscular attachment in its irregularly 

 ridged condition. 



The eighth rib of the right side is perhaps two-thirds com- 

 plete, lacking the distal end. The proximal end exhibits three 

 distinct facets, two capitular and one tubercular. Of the 

 former, that articulating with the centrum in front lies nearly 

 at right angles to the curved axis of the rib. It is small, sub- 

 ovate, and very slightly convex. The second capitular facet 

 is nearly parallel with the axis of the bone and is distinctly 

 saddle-shaped, the convex axis of the curve lying at right 

 angles to that of the rib itself. The tubercular facet lies 48 mm 

 distant and is preceded by a pronounced depression ; it is con- 

 cave along a line perpendicular to the rib axis. The shaft of 

 the rib is heavy, with sharp anterior and posterior edges and 

 with distinct muscle roughenings on its outer face. 



Dimensions. 



Distance over capitular and tubercular facets 112 mm 



Proximal capitular facet, ant.-post. diameter . . 22 



transverse diameter IV 



Distal capitular facet, ant.-post. diameter 26*5 



transverse diameter 30 



Tubercular facet, ant.-post. diameter.. 25 



transverse diameter 25 



Mid-shaft, thickness . _ _ 23 



(greatest) width 54 



Appendicular Skeleton. 



Scapulae. 



Four scapulae are present, two right and two left. Of these 

 one is more than half complete while another is little more 



* With reference to the animal as a whole. 



