r curve; the second pair 9-1/2, and the last
three 11 inches each. The largest horns ever measured by the writer were
those of a buck killed late in November, 1892, near Marathon, Texas, and
were 15-3/4 inches in vertical height and 21 along the curve.]

But few of these delicate animals have lived long enough in captivity to
permit study of the same individual through a course of years, and the
scarcity of observations made upon them in a wild state is
remarkable. That irregularity in the process would not be without
analogy, is shown by the case of the Indian sambur deer, of which there
is evidence from such authority as that king of sportsmen, Sir Samuel
Baker, and others, that the shedding does not always occur at the same
season, nor is it always annual in the same buck; and by Pore David's
deer, which has been known to shed twice in one year.

When resemblances such as those of the prong-horn are so promiscuously
distributed, the task of fixing their values in estimating affinities is
not a light one, and in fact the most rational conclusion which we may
draw from them is that they point back to a distant and generalized
ancestor, who possessed them all, but that in the distribution of his
physical estate, so to speak, these heirlooms have not come down alike
to all descendants. There is again a complicating possibility that some
may be no more than adaptive or analogous characters, similarly produced
under like conditions of life, but quite independent of a common origin,
and it is seldom that we know enough of the history of development of
any species to conclude with certainty whether or not this has been the
case. At all events, the prong-buck is quite alone in the world at
present, and we know no fossils which unmistakably point to it, although
it has been supposed that some of the later Miocene species of
_Cosoryx_--small deer-like animals with non-deciduous horns,
probably covered with hair, and molars of somewhat bovine type--may have
been ancestral to it, but this is little more than a speculation. What
is certain is that _Antilocapra_ is now a completely isolated form,
fully entitled to rank as a family all by itself.

In the musk-ox (_Ovibos moschatus_), or "sheep-ox," as the generic
name given by Blainville has it, we meet with another strange and lonely
form which has contributed its full share to the problems of systematic
zoology. Its remote and inaccessible range has greatly retarded
knowledge of