722 MR.A.D.BARTLETT ON THE AMERICAN PRONGBUCK. [Nov. 28, 
the almost erect horns. But here, again, the Chamois is seen ; in fact 
it does appear to me that we have in this animal the elements of all 
the group—forcing one to call to mind the extinct monster Sivathe- 
rium, whose wonderful remains indicate to us a beast with four horns of 
great size, and, from their form, probably partaking of the characters 
of several different existing forms; and the remarkable difference in 
form of the pair of horns in the fore part of the skull as contrasted 
with those behind, affords the ground for much speculation upon 
this subject. 
But to return to the animal under consideration. May it not be 
one of the remnants of an extinct race, whose diversity of characters 
point out to us by a very easy method how one form may slowly 
glide to the right or to the left as it were, and by little alteration 
become a Stag, an Antelope, or a Sheep? 
The consideration of the peculiar structure and remarkable varia- 
tion in the size and form of the horns of the Prongbuck has led me 
to believe that this animal may approach more nearly to the genus 
Cervus than to any other; and this idea prompts me to suggest that 
the hairy covering in which the newly-formed bony core is enveloped 
during the growth of the Stag’s horns is the homologue of, and 
should be regarded as representing, the horny part which is more 
strongly developed on the bony cores of the hollow-horned Rumi- 
nants—or, in other words, that the so-called solid-horned Ruminants 
(Cervus) shed their horny, hairy, dried, vascular covering at the 
completion of the growth of the bony core. 
This explanation of the process of the development of all horns 
appears to me more probable and natural, inasmuch as the covering 
of the deciduous horns is always, or nearly always, hairy, while these 
hairs have their terminal roots upon the inner surface, and this cha- 
racter is carried out in a most remarkable manner in the horns of 
the Prongbuck. 
The hairs connected with this structure are not only very nume- 
rous, but pass completely through the horny structure, extending 
from the base of the horn upwards above the prong. In proof of 
this, I was myself astonished when taking a cast of the internal part 
of the hollow horn; the cast, upon being withdrawn, presented the 
appearance of the specimen now before you. 
It is probable there may be objections offered to this theory of 
the growth of the so-called solid horns, seeing that, in the early con- 
dition of the budding forth of the new horn, the parts are largely 
supplied with numerous blood-vessels, and from their power to de- 
posit rapidly the bony matter, the increase of which carries out at a 
marvellously rapid rate this vascular and cuticular or tegumentary 
covering. By the rapid growth of bone, the outer covering becomes 
thin, and the circulation is cut off at the base by the increase and 
development of the bur. As its functions cease it soon becomes 
withered, and is shed, leaving the branching bony structure to fall 
off after the rutting-season. 
If this he the correct explanation of the growth of some of the 
structures now under consideration, I think a considerable difference 
