ZOOLOGICAL POSITION AND STRUCTURE 23 
that is to say, in which each hoof is symmetrical to 
a vertical line between it and its fellow, instead of 
being, as in the horse, symmetrical in itself. As 
regards the skeleton other than that of the feet, it is 
important to mention that the second, or axis, 
vertebra of the neck in all ruminants is articulated 
to the first, or atlas, vertebra by means of a short 
spout-like projection, with its concavity facing up- 
wards, arising from the front margin of the basal 
portion of the bone. This spout-like articular process 
of the axis vertebra is, however, not absolutely 
peculiar to the Pecora, as it recurs in the camels and 
llamas, while it is also foreshadowed in the horse 
and the tapir, although in those animals it is not so 
completely spout-like. In the chevrotains and the 
pigs and hippopotamuses, on the other hand, the arti- 
cular process of the axis is peg-like, or tooth-like, as 
it is in the human species ; and it is from this tooth- 
like form in the latter that this appendage has 
received its name of odontoid process. 
In the typical ruminants the spout-like form of 
the odontoid process is doubtless designed to counter- 
act the great leverage on the neck caused by the 
long and heavy horns or antlers borne by at least the 
males of so many of these animals, a similar 
structure being necessary in the case of the camel, 
where the neck is long, the vertebrae comparatively 
slender, and the head heavy. It might be urged that 
such a structure would be equally essential to 
the hippopotamus and rhinoceroses, in which the 
head is of great weight, and in the case of the 
latter animals furnished with horns which some- 
times attain a great length and weight. Here, how- 
ever, the necessary strength is supplied by the great 
