SKELETON. 



241 



The bones of the hinder limbs are also short and thick, espe- 

 cially the femur, which is scarcely more than one-third as long 

 as the tibia. The latter in length about equals the foot. The 

 relative length of the digits is as follows, the longest being 

 mentioned first: 5th, 1st, 2d, 3d, and 4th. The third and 

 fourth are of equal length, and but little shorter than the sec- 

 ond. In respect to size, the metatarsal and phalangeal bones 

 of the fifth digit are nearly twice as large as those of the first, 

 while those of the first are about twice the size of those of 

 either of the other three. As previously noticed, the three 

 middle digits of the foot are supplied with long narrow nails ; 

 the first and fifth with rudimentary ones. 



Measurements of the Bones of the Hand (Metacarpal and Phalangeal). 



Measurements of the Bones of the Foot (Metatarsal and Phalangeal). 



The hyoid bone is greatly developed. Each ramus consists 

 of five segments, its two rami being connected together by a 

 transverse segment articulating with the juncture of the fourth 

 and fifth segments. All the parts of the hyoid bone are very 

 thick, especially the transverse and anterior segments 5 rela- 

 tively much more so than in Callorhinus. In the common Phoca, 

 Misc. Pub. No. 12 16 



