BUKOTHERIA. 
79 
different. The astragalus In its oblique inner side reverses the form seen in 
the Lemurs and that of the Seals, and resembles more nearly that of the true 
Quadi’umana. From these it differs in the absence of the superior groove. 
The cuboid and navicular are not elongate as in Lemurs. The number of 
toes, supposed to be five, is that of most of the Lissencepiialous Mammals, 
belonging also to the Bears, the Quadrumana, &c. The flat claws of some 
of the genera tend to obliterate the distinction between the Unguiculate and 
Ungulate series, but they are not present on all the digits of all the species. 
The comparison of this group brings out principally affinities to the 
Insectwora and Prosimm. Besides the differences from tlie Marsiqnalia, 
already pointed out, in the genera Oxycena and Pichjmictis, the posterior part 
of the inferior border of the mandibular ramus is not inflected, as in Marsu- 
'jyialia; in Stypoloiohus {yiverrinns)^ the lachrymal canal is within the orbit, 
and not exterior to it. The reduced number of incisors in the lower jaw 
and the normal number above, are a further ground of distinction from the 
Camivorous Marsupialia. 
Comparison with the Prosimice shows that the differences consist in tlie 
sectorial character of the molar teeth and large development of the canines 
in the Eocene forms; in the short tarsal bones, and peculiar tibio-tarsal 
articulation; with convex external face of the ilium. This ensemble of 
characters can hardly be regarded as ordinal; and there only remains, to 
give character to such a distinction, the difference in the size and form of 
the cerebral hemispheres. This character, in some of the smaller living 
Lemurid<x, is not strongly marked, and in them the approximation of the 
Gyrencephalous to the Lissencephalous Mammals is at its closest. 
The differences from the Insectivora are less numerous. The only 
trenchant distinctive character upon which I can seize, in comparison with 
Mytliomys and Solenodon, is the peculiar tibio-tarsal articulation. On this 
account, and because of the rather more marked carnassial characters of 
the molar teeth, I have proposed to place the genera Ambloctoniis, Oxycena, 
Stypoloplius^ and Pidymietis in a suborder of Inseetivora, under the name 
of CreodontaA They stand also in relationship to the Lemurs, and more 
remotely to the Carnivora. 
* Oa tbe Supposed Carnivora of the Eocene of the Rocky Mountains, by E. D. 
Cope. 8vo. Philadelphia, December 22, 1875. 
