1875.] PROF. W. H. FLOWER ON THE MUSK-DEER. 181 
out in Milne-Edwards’s monograph) by which the Tragulina differ 
from the Pecora, including Moschus; but perhaps the absence of a 
distinct ridge on the lower end of the metapodium and the form of 
the lower jaw may be mentioned as examples—the coronoid process 
being much less elevated, not rising prominently above the zygoma, 
and the posterior and inferior surfaces presenting an even curve, 
without a distinct projection at the angle. It may, in fact, be taken 
for granted that, when animals of the same original type have been so 
far modified as to differ in so many important characters as have 
been shown above, the closer the scrutiny of their structure, the more 
differences in details will be revealed*. 
The question of the near affinity of Moschus to the Tragulina 
being thus eliminated, I will next proceed to consider its position 
in the group of which it is really a member. 
The Pecora or true Ruminants form, as has often been remarked, 
an extremely homogeneous group, one of the best-defined and closely 
united of any of the Mammalia. But though the original or common 
type has never been departed from in essentials, variation has been 
very active among them within certain limits ; and the great difficulty 
of subdividing them into natural groups (the ‘‘despair of zoologists,”’ 
as Pucheran calls it) arises from the fact that the changes in different 
organs (feet, skuil, frontal appendages, teeth, cutaneous glands, &c.) 
have proceeded with such apparent irregularity and absence of 
correlation that the different modifications of these parts are most 
variously combined in different members of the group. In questions 
of this kind the absolute certainty of zoological classification referred 
to above no longer holds, at least in the present state of knowledge, 
and opinion may be allowed to have sway, and results must be 
stated with some feeling of doubt and diffidence. It appears, how- 
ever, extremely probable that the Pecora very soon branched into 
two main types, the Cervide and the Bovide (otherwise the antlered 
and the horned Ruminants), the Giraffe being perhaps an early and 
since much modified offset of the former—though whether this be 
the case or whether it be regarded as a third distinct type may be 
left out of present consideration. 
Although by the general consent of all naturalists the two main 
groups thus indicated are held to be distinct, and although there 
is no difficulty in separating them by the character of their frontal 
appendages, it is by no means easy to find further characters uni- 
versaily applicable by which they can be distinguished, and which are 
necessary in the cases in which such appendages are not developed, 
as in the animal now under discussion. 
It may be said generally that the Bovide are distinguished from 
while in the form and greater freedom of the inner metacarpal and metatarsal 
bones it is further removed from them. In both genera the true molars are 
much less deeply indented by the enamel inflections, and the characteristic 
“Ruminant” crescent less distinctly defined than in the Deer. 
* Dr. J. Chatin has recently described the muscles of the limbs of Hyomoschus, 
and finds, as might have been anticipated, that they differ much from those of the 
Pecora and rather resemble those of the Swina (“‘ Observations swr la Myologie 
de l Hyomoschus,” Annales des Sciences Naturelles, 5° série, t. xv. 1872, p. 1). 
