(■>2 
TEliTIAKY YEliTEBEATA OF TJIE FAY^M. 
of Arsinoitherrimi, lhoi]<^li in tlie absence of associated scries there may l)e some 
doubt about the exact ))ro|)ortions of the limb-bones. Text-fig. 37 is a view of the 
|)elvis and liind limb seen from the front, and shows the great width of the pelvis, 
the ])ro])ortions of the femur and tibia, and the structure of the tarsus. Both the 
figures are al)ont one-sixteenth natural size, the animal having stood about T7G 
metres (about 5 ft. 9 in.) at the withers and measured about 2‘96 metres (9 ft. 9 in.) 
from the snout to rump. 
The determination of the systematic position of the Barypoda is rendered specially 
difficult from the circumstance that Arsmoitherium, the only member of the group 
at present known, is a highly specialised terminal form of a series of which the 
earlier terms are still undiscovered. Nevertheless some attempt may be made to refer 
this animal to its place in the system, for although in many respects so specialised, in 
others it retains primitive characters, and even where the degree of specialisation 
is great, as in the case of the teeth, it may still be possible to arrive at a fairly clear 
idea of the conditions that must have existed in the earlier types. 
From the account of the skeleton given above it will be seen that there is no doubt 
that the Barypoda form a subdivision of the Ungulata, belonging to that section 
of the order including the Elephants, Hyracoids, and Amblypoda, to which the 
collective name Subungulates is sometimes applied. To determine the relations 
of the Barypoda with the other Ungulates comparison must be made with (1) the 
Ih’oboscidea, (2) the Amblypoda, (3) the Flyracoidea, and (4) some of the South- 
American Ungulates. The last of these comparisons is necessary because Ameghino 
has suggested that the Ethiojnan and S. -American regions were closely connected 
in the later Cretaceous and early Tertiary times, and he considers that many of the 
main groups of Ungulates {e. g. the Hyracoids and Proboscidea) originated in S. America 
and subsequently migrated into Africa. It is not jiossible or desirable to discuss 
these questions fully here, but some allusion must be made to them. 
Comparison of Arsinoitherium with the Proboscidea shows that in the structnre of 
the skull, in the form of the molars, and in the persistence of the complete series 
of teeth without diastemata it differs entirely from any member of that suborder. 
In the skeleton, on the other hand, there are some similarities, but these seem to be 
merely parallel modifications due to great size and weight in the two groups, while, 
(»4i the other hand, differences of such fundamental importance exist {e. g. in the 
structure of the tarsus) that any possibility of close relationship may be excluded. 
Comparison with the Amblypoda shows that many points of resemblance in the 
skeleton exist, but, as in the case of the Proboscidea, these are probably nearly all 
the results of parallel evolution and are modifications dc])cndiug mainly on increasing 
bulk and weight. On the other hand, the great similarity of the structure of the 
ti’.rsus in the two cases cannot be so explained, but is ])robably a primitive character 
derived from similar Condylarthrous ancestors in the two cases. In the skull the 
