198 



SERIAL AND INTERLOCKING CARPUS 



Matthew. 1 He has pointed out that in some ancient Ungulates 

 the carpus is not serial but interlocking, even in forms which 

 belong to the earliest Eocene groups,' such as the genus Protolambda 

 among the Amblypoda. Now in the fore-foot of Meniscotherium 

 and the living Hyrax there is a separate centrale which is wanting 

 in the greater number of Ungulates. The absorption, that is the 

 practical dropping out of this bone, would restore to an interlocking 

 carpus the serial arrangement ; while on the other hand, by the 



B 



IV 



IV 



FIG. 112. Bones of the maun* A, of the Indian Elephant, Elephas indicus. x J. 

 B, of the Cape Hyrax, Hyrax capensis. x 1. c, Cuneiform ; cc, centrale ; I, 

 lunar ; in, magnum ; p, pisiform ; R, radius ; td, trapezoid ; tin, trapezium ; s, 

 scaphoid ; u, unciform ; U, ulna. (From Flower's Osteology.) 



fusion of this bone with the scaphoid, the interlocking disposition 

 would be maintained. 



The gradual perfecting of the fore- and hind-limbs as running 

 organs has been put down to the advent of the grasses, and the 

 formation of large plains covered with this herbage. The same 

 reason would also be in harmony with the equally gradual change 

 in the shape of the molar teeth, from a tubercular form calculated 

 for a mixed or even a carnivorous diet, to the natter crushing sur- 

 faces exhibited by the lophodont teeth of later Ungulates. Strong 



1 Bull. Amer. Mus. Nat. Hist. ix. 1897, p. 321. 



