MUSEUM OF COMPARATIVE ZOOLOGY. 



53 



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 second. In fespect to size, the tarsal and phalangeal bones of the fifth 

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

 are about twice the size of those of either of the other three. As pre- 

 viously noticed, the three middle digits of the foot are supplied with long 

 narrow nails ; the first and fifth with rudimentary ones, scarcely visible in 

 the skin but quite distinct in the skeleton. 



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 an- 

 terior . segments ; relatively much more so than in Callnrhinm. In the 

 common Phoca the hyoid bone is reduced almost to a bony filament. 

 The length of the hyoid bone in the present species is 270 mm.; of the 

 transverse segment, G5 mm. ; circumference of the transverse segment, 45 

 mm. ; of the segment at the thickest part, 95. 



