502 THE EOCENE PEEIOD. 



u. 



Uo8teriorlyr«rti'=^l 008 



Diameters posterior lumbar < < transverse 015 



( anteroposterior 015 



Height of ueural canal 006 



Expanse of metapophyses 018 



Length of sacram .038 



vertical .006 



transverse 013 



I * •„ 1 < vertical 0065 



\ posteriorly I 

 Diameters of first caudal < (transverse 010 



( anteroposterior - 010 



c 



Diameters anteriorly { 

 t 



The glenoid cavity of the scapula is an oval, acuminate anteriorly to an 

 apex pi'ojecting downwards. The coracoid is prominent, and strongly in- 

 curved. Length of cavity, .009; width, .006. From a different individual 

 from the one last described. 



The humerus is much like that of PJienacodus vortmani, differing in the 

 smaller size, less prominent tuberosities, and slightly different condyles. 

 The shaft is flattened anteroposteriorly below the head, but there is no 

 bicipital ridge, and the groove is restricted to the notch between the tuber- 

 osities. The latter project little, the gi-eater not at all anteriorly, but it 

 rises proximally into a convex crest. The teres minor fossa is flat, and the 

 teres major ridge is distinct and extends on the proximal two-fifths of the 

 length. The subscapularis fossa is small and flat, and is bounded by an 

 angular ridge which rises upwards and outwards, forming the prominence 

 of the lesser tuberosity. The external epicondyle is wanting. The inter- 

 nal is prominent and compressed, and sends a bridge over the epitrochlear 

 foramen. The latter is as large as in the Creodonta, larger than in the spe- 

 cies of PJienacodus, but not so large as in PeriptycJms rhabdodon. The crest 

 of the external distal region is acute, but not very prominent. The shaft 

 above the coronoid fossa is triangular, the anterior angle obtuse, the exter- 

 nal acute. The condyle has an internal flange, and external to that a prom- 

 inent rim not seen in Phenacodus nor Periptyclms. It is represented by a 

 short cylinder in Biplartlira generally, and the edge of it is turned up in 

 Hyracotlierium venticolum. In the M. terroeruhrm it is a rim springing directly 

 from the contraction of the roUei', on the anterior side only. The convexity 

 of the roller is marked, but too wide to be an intertrochlear crest, such as 

 is seen in Hyracotherium and other Biplartlira. As compared with the Phe- 

 nacodus vortmani, this humerus has a generally weaker structure. 



