198 SERIAL AND INTERLOCKING CARPUS CHAP. 
Matthew.’ 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 hving 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 
Fic. 112.—Bones of the manus A, of the Indian Elephant, Hlephas indicus. x 
B, of the Cape Hyrax, Hyrax capensis. x1. c, Cuneiform; cc, centrale; / 
lunar; m, magnum ; p, pisiform; R, radius ; ¢d, trapezoid ; tm, trapezium; s 
scaphoid ; w, 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 flatter crushing sur- 
faces exhibited by the lophodont teeth of later Ungulates. Strong 
1 Bull. Amer. Mus. Nat. Hist. ix. 1897, p. 321. 
