80 
DE. W. KOWALEVSKY OX THE 
are exaggerated in the true Ruminants. The trapezoid and the second cuneiform 
are always, even in the cartilaginous state, confluent with the magnum and third cunei- 
form, and can be detected only as distinct points of ossification. The. rudiments of the 
lateral digits are generally preserved as slender elongated bones in the metacarpus, 
especially in Deer, .much more seldom in the metatarsus. In the fossil Ruminantia 
from Auvergne these lateral rudiments are present, as a rule, on both the fore and hind 
limb (Plate XXXYII. fig. 16, n.). The rudiment of the fifth metatarsal is usually free, 
and has even a small facet on the cuboid; while the second metatarsal, being jammed 
in between the inner enlargement of the third metatarsal and the posterior beak-like 
prolongation of this digit, has generally coalesced ; but its proximal extremity is mostly 
free, and articulated with the first cuneiform (and this is sometimes to be seen even in 
living Ruminantia). 
The upper and posterior beak-like prolongations of the middle metatarsals of Pari- 
digitata constitute a very characteristic feature of these bones ; they grow larger and 
larger with the reduction of the pes, and are firmly pressed together by a special process 
of the cuboid and the first cuneiform in those genera in which locomotion is almost 
entirely performed by the two middle digits. Finally they coalesce, and the confluence 
of the metatarsals seems to proceed from these processes downwards, as is to be seen at 
a certain age in the metatarsus of Dicotyles. 
Metacarpus and Metatarsus of Hyopotamus and Diplopus. 
Having thus discussed at some length the shape and mutual connexions of the bones 
which compose the fore and hind limbs in the chief fossil and living Paridigitata, 
our task is made much easier in reference to Diplopus and Hyopotamus ; and without 
dwelling too long on the description of very minute particulars of these bones, which to 
a certain extent are visible in the Plates, I shall merely state the chief features they 
present to the observer, and the points of agreement or difference with the corresponding- 
bones of allied genera. 
I begin with the metacarpals of Hyopotamus , or the tetraclactyle form, and will 
afterwards pass to the didactyle Diplopus. The restoration of the manus of Hyopotamus 
from Puy is given in Plate XXXVII. fig. 20, \ nat. size, and the upper part of the 
same manus, fig. 5, Plate XXXVIII. The separate bones belonged to different indi- 
viduals, and were not found in connexion. The fourth metacarpal especially is defective ; 
but it is the only specimen of this digit I could find in the collections from Puy ; it comes 
from a very young individual, and is therefore too small for the adult unciform by 
which it is supported. I have seen the same bones from Hempstead, but somewhat rolled. 
The interlocking of the two middle metacarpals is effected in the usual way, the 
radial margin of the fourth being thrust under the ulnar prolongation of the upper 
margin of the third (Plate XXXVIII. fig. 5). This ulnar prolongation of the third 
metacarpal going to meet the unciform is very oblique in the Hyopotamus ; its axis 
forming, approximately, an angle of 45° with a horizontal line. In the Suidge, as well 
