51 



the bone, for the junction with the antecedent and following bones of 

 the sternum ; the remaining eight articulations are more concave, and 

 are situated in pairs, two on the upper and two on the lower surface of 

 each side ; they receive portions of the bifid extremity of the ossified 

 sternal ribs, which are articulated to the interspace of the sternal bones. 

 A similarly complex articulation of the ribs with the sternum exists in 

 the Great Ant-eater {Myrmecophaga jubata) . 



3 ! 6. A sternal bone, apparently the last of the series, since it has only the 

 surface on the anterior part for the antecedent bone, and none on the 

 posterior part : the inferior lateral costal articular surfaces are confluent, 

 or single, on each side, and almost meet upon the posterior surface of 

 the bone ; they appear to have received the ossified cartilages of the last 

 pair of true ribs, whicli must have differed from the rest by terminating 

 in a simple expanded, instead of bifurcate, extremity. 



31/. The right clavicle. It presents a strong sigmoid curvature ; is expanded 

 at both extremities, that next the sternum being the largest ; and the 

 intermediate, sub-cylindrical shaft is traversed below by a broad rough 

 oblique ridge. 



318. The right scapula. In this bone may be noticed the supra-spinal foramen 



and the osseous arch connecting the acromion with the coracoid ; by 

 both of which characters Cuvier first detected the affinities of the Mega- 

 therium to the Sloths [Bradypus). 



319. A portion of the left scapula, including the acromion and glenoid cavity. 



320. The left radius. The concave proximal articular surface is nearly circular ; 



the rough tuberosity for the insertion of the tendon of the biceps is well 

 developed : the outer margin becomes thinner, and gradually subsides as 

 it extends downwards : in the figure of the same bone in the skeleton of 

 the Megatherium at Madrid this ridge stands out like a well-defined pro- 

 cess. The posterior surface of the present radius presents a moderate 

 and equable convexity ; there is a rough convex protuberance above the 

 styloid process ; the shaft of the bone gradually expands to near the 



h 2 



