86 
DR. W. KOWALBVSKY ON THE 
smooth anteriorly, the articular ridge for the first phalanx being limited to the posterior 
or palmar half of the distal surface. 
The lateral digits were completely developed in Hyopotamus and, no doubt, played 
an active part in the process of locomotion. The second metatarsal, seen from the 
inner side in Plate XXXVIII. fig. 2, n., is articulated to the second cuneiform by a 
nearly circular, flat proximal facet ; this facet occupies the whole upper, somewhat 
attenuated, head of the second metatarsal ; the anterior part of this proximal head is 
pressed against the third cuneiform, as seen in fig. 2, n. c 3 . On its postero-tibial side, 
a little lower down, is seen another elongated facet, to which was articulated the first 
cuneiform, although this last bone was not to be found in any of the collections 1 
visited. The shaft of the second metatarsal was closely pressed against the third, and 
reached very low down the metacarpus, considerably lower than in the Hog; and in 
my restoration of the pes (Plate XXXVII. fig. 21) the lateral digits, as I am aware now, 
are too much shortened. The section of the second digit is perhaps more elongated than 
in my figure. The distal extremity is unsymmetrical, but very well developed, the ridge 
for the first lateral phalanx being very high and confined to the back part of the distal 
end. . The truncated posterior border of the proximal end of the second metatarsal is 
very characteristic of all Paridigitata which have retained the lateral digits : it is to be met 
with in the Suina, in Cainotherium , and even in. Hippopotamus ; this truncature is 
intended for the first cuneiform, which articulates with the navicular, with the posterior 
part of the small second cuneiform, and, by a large facet, with the truncated posterior 
edge of the second metatarsal *. 
Th e fifth (Plate XXXVIII. fig. 1, v., Plate XXXVII. fig. 21, v.) or outer metatarsal 
presents, at its proximal end, a triangular facet, corresponding to the facet v. on the 
distal side of the cuboid (Plate XXXVIII. fig. 10) ; the posterior end of this fifth 
digit is prolonged backwards into a projection which has very nearly the same antero- 
posterior length as the fore or articular part. The inner or tibial side has a half 
reniform facet for the articulation with the fourth metatarsal. The section of this 
digit in the middle gives a somewhat roundish outline ; its general shape is oval, the 
proximal third is a little curved forwards to fit more exactly the outline of the neigh- 
bouring fourth metatarsal. 
The Metatarsals of Diplopus. 
Of these I found several specimens in a perfect state of preservation in the 
collection of the British Museum f . They are all said to come from Hordwell ; 
* In Hyopotamus, although the third cuneiform has no regular truncated edge, as in Hippopotamus (Plate 
XXXVII. fig. 10, c 3 ) and Antliracotlierium, for the articulation of the second metatarsal, still this metacarpal, 
owing to the fact that the second cuneiform is situated a little higher than the third, is allowed to touch this 
last, remaining thus true to typical relations. 
f On my second visit to Puy, after this paper was written, I saw, in the collection of Hr. Vinay, a detached 
second metatarsal of unusually large size. It belonged to the large species, and, judging by this hone, all the 
four metatarsals of the larger species of Hyopotami were nearly subequal, as in the recent Hippopotamus. 
