ABT. 15 ANATOMY OF THE EARED AND EARLESS SEALS HOWELL 7 



thicker and longer upon the cranial border and thinner and shorter 

 upon the caudal one. Each digit had a minute circular nail set 

 within a pit in the integument, located approximately at the end of 

 the terminal phalanx, and a cartilagenous prolongation of the digits 

 extending considerably farther. The distance from the metatarso- 

 phalangeal joint of the first digit to the nail was 85 mm., and from 

 the nail to the termination of the digit, 65 mm. The entire manus 

 was rather stiff, without free movement of the digits, and there was 

 a minimum of possible abduction or adduction. The interdigital 

 membrane reached to the ends of the digits, and the sole was naked 

 and wrinkled. In the Phoca the external part of the foreleg meas- 

 ured but 100 mm. from the axilla and was not highly modified into 

 a paddle. The manus was short and broad and hairy upon the palm, 

 it was abducted more than in most mammals, and the articulations of 

 the carpal bones were loose to the touch. As in the otariid the first 

 digit was the longest, and there was sequential diminution to the 

 fifth, but in that animal the difference in length between these two was 

 very marked and in the phocid very slight. There are broad, heavy 

 nails upon all the digits of the latter, and there are no cartilagenous 

 extensions. 



The crotch, between the hind limb and tail, was in the otariid at the 

 most caudal of the muscles between the innominate and the leg, but in 

 the Phoca conditions differed, for there was a considerable distance 

 between the crotch and the last muscles, this being occupied by tough 

 fatty tissue. In the former animal the crotch was opposite the middle 

 of the calcaneal tip (heel), while in the phocid it was located about 

 20 mm. farther caudad, a distance not sufficient to make much differ- 

 ence in the mobility of these members. As discussed more fully 

 elsewhere the hind foot of the otariid readily assumes a plantigrade 

 position at an angle of 90° with the shank, while in the Phoca the 

 angle so formed, without undue forcing, does not exceed 60°. From 

 the crotch the hind limb of the latter measured 220 mm. in length, 

 and of the otariid, 260. When viewed from the rear with joints ag 

 relaxed as it was possible to get them in the preserved specimens the 

 plantar planes of the feet of the otariid presented the appearance of a 

 very steep-sided V, and in the Phoca^ of an equally steep-sided A. 

 Pronation and supination corresponded with these positions, but so 

 little of the leg projected from the body that one could not determine 

 the precise amounts. In both animals the first and fifth digits are 

 considerably the most robust and the longest. In the Zalophus only 

 there is also a cartilagenous extension to each digit. The distance 

 from the metatarso-phalangeal joint to the nail of the first digit 

 measured 77, and from the nail to the tip of the toe, 78 mm. The 

 cartilages of the middle three digits were relatively a bit shorter, and 

 that of each toe projected beyond the interdigital membrane, as shown 



