442 



MEMOIRS OF THE CARNEGIE MUSEUM. 



centra is complete, especially in fully adult or old individuals, there being little 

 or no trace of a suture. 



Caudal Vertebrae. Twenty-six vertebrae have been attributed to the tail. 

 This is thought to be approximately correct, inasmuch as seventeen were found in 

 consecutive order from the first to and including the seventeenth. The seventh 

 caudal is the last with a complete neural arch, and the eighth is the last with 

 traces of a transverse process. The tail as a whole is moderately long and tapers 

 to a fine point as indicated by many very small vertebrae found in the collection. 



Ribs. — The ribs, even the posterior, are rather long. In the anterior region 

 they are flat, though not broad, while further back their cross-sections have a 

 tendency to be more trihedral. There are well-defined tubercular facets throughout 

 the entire series. Altogether the thorax forms a rather solid cylinder. 



Fig. 29. Diceralherium cooki Peterson. No. 2817, Coll. Carnegie Museum. 1, Dorsal view of sternum; 

 2, ventral view of same; 3, lateral view of same. X h 



Sternum. Fig. 29. The sternum was described in part as follows:'-^ 'The 

 manubrium is an elongated, laterally compressed, and vertically deep plate of 

 bone. Anterior to the contact for the first pair of ribs there is a long heavy process, 

 extending forward, and constituting the greater half of the entire length of the 

 presternum. Posteriorly the bone is slightly expanded transversely and has a 

 rough surface for the attachment of the mesosternum. The first two segments 

 of the latter are somewhat deeper than wide. The j^osterior end of the fourth 

 sternebra is nearly square in outline, while the fifth and sixth are broader than deep.' 



2S Peterson, 0. A., Ann. Car. Mus., Vol. VII, 1911, p. 277. 



