OSTEOLOGY OF THE HYOPOTAM1D JE . 
71 
•supported by the second cuneiform (c 2 ), and its tibial margin touches the third cuneiform 
(just as the homologous parts on the fore foot do) ; the first digit is entirely lost, and its 
typical tarsal bone, the first cuneiform, aids in supporting the second digit (Plate XXXVII. 
fig. 10,0,). 
This should be the place to consider the structure of the feet in the Suina ; but, as in 
the recent members of this family, owing to the overdevelopment of the middle digits, 
the typical relation between the bones is a little changed, I will describe it after having 
treated those Paridigitata which preserve this typical relation unchanged. 
Of the fossil Paridigitata whose skeleton is known to us with any thing amounting to 
completeness, we have only the Anoplotherium and Xiphodon; and we shall see by- 
and-by with what wonderful persistence the typical relations are adhered to in the 
skeletons of these animals, notwithstanding the great reduction of the number of their 
metacarpals and metatarsals. 
As the Anoplotherium tridactylum is certainly a less-reduced form than the species from 
the gypsum, and as, except a sketch in Gervais’s ‘ Paleontologie Fran^aise,’ there are no 
good drawings of its extremities, I represent them on Plate XXXVII. figs. 2, 11, from the 
original specimens of Bravard now in the British Museum. Though the number of digits 
on the fore and hind limbs is odd, it is nevertheless a very typical Paridigitate, and 
differs from the Paris Anoplotherium only in this respect, that the second digit, which is 
represented only by a small rudiment in the animal from Montmartre, is developed to 
a complete (though short) digit in the Anoplotherium from the lignites of Vaucluse. 
The manus of the Anoplotherium is so well described by Cuvier that I will not enter into 
any details, and only point out its chief peculiarities. As seen in Plate XXXVII. fig. 2, 
this manus is entirely true to the general type : the interlocking of the two middle meta- 
carpals is effected in the same way as described above ; the fourth metacarpal is supported 
by the unciform ; the third hangs to the os magnum, and sends a prolongation of its 
ulnar margin to meet the unciform ; the second, though too short to touch the ground, 
is complete and supported by the trapezoid, and it sends a projection to articulate 
with the os magnum ; the trapezium aids in supporting the short second digit. At the 
outer margin of the foot there exists a rudiment of the fifth digit, leaning against the 
unciform and the ulnar margin of the fourth metacarpal. 
The pes of Anoplotherium tridactylum (Plate XXXVII. fig. 11) shows us the same 
typical persistence in the relation of the bones. The interlocking of the two middle meta- 
tarsals takes place, as usual, by a process from the fourth fitting into an excavation of the 
third metatarsal ; this last is supported by the third cuneiform (c 3 ). As the second digit 
is developed, the corresponding bone, the second cuneiform (c 2 ), very small or nearly obso- 
lete in the Paris Anoplotherium , is largely developed in the A. tridactylum , and supports 
the second digit; the first digit is absent, and its tarsal bone, the first cuneiform (cj, 
aids in supporting the second digit. 
As the chief difference between the Anoplotherium from the gypsum of Paris and 
the A. tridactylum lies in the development of the second digit and its corresponding 
