No. 2301. DESCRIPTIONS OF PLEISTOCENE VERTEBRATA—HAY. 621 



comparison. A part of the shaft of a radius (Cat. No. 10142), 185 

 mm. long, has a breadth of 47 mm. at about the middle of the whole 

 bone. A nearly complete left third metacarpal (Cat. No. 10143) is 

 present. 



The following comparative measurements are given: 



Measurements of third metacarpals. 



No. 

 174960 



U.S. 

 N. M. 



Total length 



Width of upper end 



Side-to-side diameter at middle.... 

 Fore-and-aft diameter at middle.. 

 Side-to-side diameter at lower end 



246 

 56 

 32 

 27 

 54 



It will be seen that the fossil bone is only about one-tenth longer 

 than the recent one. It is not at all improbable that it belonged to 

 the smaller horse, but the metacarpal described as representing that 

 horse is only 50 mm. wide above. 



A first phalangeal bone (Cat. No. 10144) of the third digit has a 

 length, in the median plane, of 88 mm.; that of the hinder bone of 

 the recent horse being 77 mm. The width at the upper end is 63 

 mm.; that of the recent horse, 57 mm. It is not larger than corre- 

 sponding bones of supposed Equus pacificus from Christmas Lake, 

 Oregon. A second phalange (Cat. No. 10146) is 55 mm. wide at its 

 lower end; that of the recent horse, 44 mm. A hoof phalange (Cat. 

 No. 10147) is 78 mm. wide. The latter bone appears to belong to a 

 hinder limb. In the part of this collection that was made for the 

 American Museum of Natural History there are a second and a third 

 phalangeal which appear to belong to a fore limb. These have that 

 museum's catalogue number, 14362. The second phalange is 63 mm. 

 wide at the upper end; 55 mm. wide at the lower end. The hoof 

 phalange is 84 mm. wide. This phalange is more broadly rounded 

 than that supposed to belong to the forefoot. 



MYLOHYUS ? species indeterminable. 



In the collection there is a fragment (Cat. No. 10153) of the upper 

 end of the ankylosed lower arm bones of the right side. The olecranon 

 process is likewise broken off. The whole fragment is only 80 mm. 

 long, and it extends 65 mm. below the greater sigmoid cavity. The 

 width of the radius in this cavity is 29 mm. At the lower end the 

 fragment has a width of 26.5 mm.; a thickness of 17 mm. On the 

 hinder face of the fragment, at a distance of 42 mm. below the front 

 of the greater sigmoid cavity, is a foramen. A specimen of Platygonus 

 from a fissure near Cumberland, Maryland, measures 160 mm. from 



