42 
DR. W. KOWALEVSKY ON THE 
dentition Avithout being made much wiser by it. The history of palseontology swarms 
with such examples ; but the discovery of a single carpal or tarsal bone very often 
clears the Avhole question, by showing in the most unmistakable manner the true 
affinities of a fossil form. Seeing this great importance of the carpal and tarsal, 
metacarpal and metatarsal bones, I feel obliged to enter into more minute details than 
I have done in the case of the long bones of the limbs ; and I shall try to show how 
constant and important are the characters which we may derive from the study of these 
small bones, and what excellent data they may furnish towards a complete understanding 
of the development in time of the large and extensive group of modern Ungulata. As 
in one of my former memoirs* I tried to follow this course in reference to the Impari- 
digitata, I will confine myself in this paper only to the Paridigitate series. As the chief 
differences for subgeneric or specific division of the Hyopotcimidce are furnished by the 
bones of the feet, I shall describe these first, leaving the skull and the dental characters 
to be treated afterwards. 
Although I found at the British Museum and in the private collection of M. Aymard 
at Puy very extensive materials for the restoration of the fore and hind feet, still it 
is to be regretted that as yet we have never found a complete fore or hind foot, in its 
natural connexion, belonging to the same individual ; still less was there a chance 
of finding the bones associated in an undoubted manner with a certain set of teeth : all 
bones of the Hyojyotaiims occur very much scattered, and no complete skeleton belong- 
ing to one individual has ever been found, at least to my knowledge. The happy cir- 
cumstances which enabled Cuvier to refer, without any doubt, certain sets of bones to 
certain skulls (as whole skeletons were sometimes found in the gypsum of Montmartre) 
did not favour my research. But if the actual connexion of specific bones and teeth 
should still remain not entirely cleared up, the general osteology of the genus will not 
in the least suffer by it ; and with the materials I had at my disposal, I am conscious of 
being able to reconstruct both generic forms in a very satisfactory manner, though 
even for the carpus I had no complete set of bones belonging to one individual. But in 
certain series of animals the peculiar form and general relations of these bones are so 
constant, that we may expect variations only in the smallest particulars ; so that the 
general structure of the feet and the mutual relation of the carpal and tarsal bones 
between themselves, and to the bones of the metacarpus and metatarsus, may be con- 
sidered undoubtedly settled for the Hyopotamidce. To make my description more 
clear to the reader, I will take care to make comparisons with animals accessible to every 
naturalist ; and I think that for the full comprehension of the relations of these 
irregular bones drawings are wholly inadequate, and a direct comparison Avith the feet 
of a pig and a ruminant should be resorted to. 
Notwithstanding the great external diversity of the recent Ungulata, taking both 
series of Paridigitata and Imparadigitata, Avhere we meet with animals so different in 
their aspect, habits, and size, running through all the intermediate stages from a rabbit 
* “ Sur l’Anchitherium,” Mem. Acad. St. Petersbourg, 1873. 
