and its Position in the System. 325 
the inner surface, especially near the edge of the sheath. The 
giraffes, on the other hand, have the same permanent cores, which 
are covered with a hairy skin, like the rest of the body, which 
covers the horn during the entire life of the animal. 
The horns of the deer, with which Mr. Bartlett compares those 
of the Prongbuck, on the other hand, are only developed at a 
certain season of each year; and while they are being expanded, 
they are covered with a soft velvety skin containing a number of 
large blood-vessels: these vessels become obliterated and the 
skin falls off when the horns are fully developed; and at the 
end of the season the horns themselves fall off, leaving only a 
burr on the frontal bones. 
Now in the Prongbuck the core of the horn is permanent, 
vascular, and exactly like the core of the horns of the true hol- 
low-horned Ruminants, very unlike the deciduous horn of the 
deer, and showing the true affinity of the genus to the antelope 
and goat, with which it has been usually associated. It indeed 
only differs from the normal structure of that of the animals of this 
group in the core being covered with a case formed of aggluti- 
nated hair, which falls off annually, and is replaced by another 
case formed between its cavity and the outer surface of the core. 
The surface of the core is covered with a vascular skin, which 
secretes this deciduous coat of agglutinated hair, like the vascu- 
lar coat that secretes and gradually enlarges and thickens the 
horny permanent case of the horns of oxen, sheep, and goats. 
It is to be observed that the horny case of the core of all these 
animals is formed of agglutinated hair; but the hairs of the 
horns of the oxen, sheep, &c. are more closely agglutinated 
and regularly placed, forming a denser substance than the 
porous horny case of the Prongbuck, in which the several hairs 
of which it is composed are to be seen by the naked eye, and 
some of them projecting beyond its surface. 
I think that the above observation proves that the Prongbuck 
is more nearly allied to the typical hollow-horned Ruminants, 
with which it has been placed, than with the deciduous-horned 
deer, with which Mr. Bartlett proposes to unite it. Indeed it 
only differs from them in the outer case of the horn being po- 
rous and formed of loosely agglutinated or, rather, felted hairs, 
and in the case being deciduous and renewed annually, instead 
of being permanent and strengthened by internal laminz so as 
to form a hard horn. 
There is no doubt that this peculiarity of the structure and 
derivation of the sheath, or rather case, of the horns affords a 
very good character to separate the Prongbuck from the other 
hollow-horned Ruminants; and I suggest that it should be formed 
into a family, which should be called Antilocapride, of equal 
