158 MR. H. a. SEELEY ON OSSEOUS EESEMBLANCES 



end on the radial side of the bone. These conditions are repro- 

 duced in Bats, where the humerus is proportionally much longer. 

 Many pachyderms, like the Horse, have a radial crest ; and the 

 Walrus, Seal, Sloth, &c. have no marked olecranon-pit. The 

 head of the mammalian humerus is never so much compressed 

 from side to side as in the Crocodile, and usually has a trochau- 

 teroid process in front of the articular surface, though this is 

 wanting in Whales and in Man. 



The radius of the Crocodile oiFers no striking modification of 

 its own, and is chiefly distinguished from mammals by its straight 

 and more cylindrical shaft, and freedom from ridges, which are 

 but faintly developed even when present. In proportion and 

 form the ulna of the Crocodile is best matched by the African 

 Ostrich, and is sufficiently distinguished from most mammals by 

 wanting the olecranon-process, which, however, is sometimes but 

 little developed, as in the Sloth ; but the mammalian ulna has not 

 often the stoutness found in the Crocodile. 



The carpus of the Crocodile is peculiar in consisting of a large 

 and elongated scapho-lunar, a smaller elongated cuneiform, and a 

 pisiform in the proximal row. Distally there is a small sub- 

 quadrate bone under the cuneiform. If it represents the bone 

 in the same position in Chelonians, then the bones usually deve- 

 loped as a distal row of carpals have no existence *. In the 

 Grrampus {Delphinus orca) the proximal row of carpals similarly 

 consists of two bones ; but they are not elongated, and there is no 

 pisiform bone ; similarly there is a very small distal carpal. But 

 most mammals have two rows of many-sided carpal bones. 



The form and proportions of the metacarpal bones and pha- 

 langes is very similar to that of clawed mammals. Mammals, 

 however, usually have the proximal end of the bone flatter and 

 the distal end more globular ; sometimes (e. g. the Lion) the 

 metacarpals have a similar tendency to overlap each other at the 

 proximal end. In number of phalanges in the long fingers Cro- 

 codiles do not equal the Cetacea. 



The pelvis of the Crocodile is peculiar in the exclusion of the 

 pubis from the acetabular articulation of the femur. In the 

 Horse, Llama, and many mammals an approximation to such an 

 arrangement may be detected ; and in Myrmecophaga the pubis 



* See, however, Gregenbaur's ' Vergleicheuden Auatomie,' erstes Heft, 1864, 

 pi. 3. 



