64 
DK. W. KOWALEVSKY ON THE 
metatarsal in this specimen has a very slight truncature or oblique facet, by means of 
which this third metatarsal touched the second cuneiform, a deviation from typical 
relations which is enormously developed in the Hog (Plate XXXVII. fig. 12, in. c 2 ) ; 
the proximal surface of the rudimental second metatarsal (Plate XXXVIII. fig. 4, n. r) 
is therefore a little lowered in this specimen, to allow the second cuneiform to touch the 
third metatarsal. On the contrary, id two other specimens not figured, the relations 
remain true to type, and it is the third cuneiform which gives a small facet to the 
rudiment of the second metatarsal. 
I have found, moreover, in the British Museum a specimen of the Diplopus from 
Hordwell in which the two cuneiforms (2 + 3) had coalesced in the same manner 
as the two cuneiforms of the Hyopotamus of fig. 2. The distal surface of these two 
coalesced cuneiforms is given in outline below fig. 4, Plate XXXVIII., to show its cor- 
respondence with the proximal surface of the third metatarsal ; and it answers so exactly 
to the third metatarsal with the coalesced rudiment of the second, figured in fig. 4", 
that one may think they belonged to the same individual [my coalesced cuneiforms, 
however, are from the other (right) side] ; and the correspondence to the figured foot is 
so exact that even the second cuneiform presents a small facet (the shaded bit of the 
outline below fig. 4) to the third metatarsal. So that in this specimen the overdeveloped 
third metatarsal seeks additional support from an adjoining tarsal bone. In the Suina 
it accomplished the passage long before the loss of the second lateral digit, as seen in 
figs. 12 and 13, Plate XXXVII. 
A similar case is described in my Memoir on Anchitherium * : here also the third 
cuneiform became, in the same way, confluent with the second, to pave the way for 
the overdeveloped third (and single) metatarsal to enlarge and usurp the second cunei- 
form, which bone typically belongs to the second digit. 
The first cuneiform is absent ; and, judging from the absence of a facet for this bone on 
the posterior prolongation of the third metatarsal in Hyopotamus (Plate XXXVIII. 
fig. 2), we may infer that it did not articulate with it; but in Diplopus such facet 
on the posterior prolongation of the third metatarsal is clearly seen (fig. 4", fc J, 
and furnishes a conclusive proof that the first cuneiform was articulated to it in the 
same manner as in the Hog. Above, it was articulated to the somewhat convex pos- 
terior facet of the navicular (seen in figs. 4 and 2, Plate XXXVIII.), then touched the 
back part of the small second cuneiform, and, being prolonged lower down, leaned 
against the posterior part of the second metatarsal (as proved by a facet on this bone) 
in Ilyopotamus (fig. 2), or against the rudiment of this second metatarsal in Diplopus , as 
seen in fig. 4, Plate XXXVIII. In this latter the first cuneiform was probably thrust 
like a wedge between this rudiment and the posterior prolongation of the third meta- 
tarsal, in the same way as it is to be seen on a hog’s tarsus (Plate XXXVII. fig. 12). 
Metacarpus and metatarsus. — When I began to study the structure of the anterior 
and posterior extremities of the Anthracotheridse and Hyopotamidse in the collections of 
* Hemoires de l’Academie de St. Petersbourg, 1873. 
