from 48 to 56, and in Jf. javanica it may even be as high as 64. The extent to
which these scales occur on the tail in the different species also affords materials
by which to separate the three forms. In Jf. pentadactyla the average number
is 14, in Jf. aurita 16 to 20, and in Jf. javanica as many as 30. The Indian
ant-eater has also, much longer fore claws than Jf. javanica, and in this respect it
is more closely allied to Jf. aurita, but in all the species the hind claws are
shorter than those on the fore feet, but in Jf. javanica the difference that exists
between them is not at all well marked, and the claws are much less powerful than
in the two others. Jf. pentadactyla is distinguished from Jf. javanica by its much
broader and less tapered tail; and in this respect it is closely related to J f aurita,
the form to which it is most affined. In Jf. 'pentadactyla the tail stands to the
body and head in the proportion of 100 to 100, in Jf. aurita of 71 to 100, and in
Jf. javanica of 82 to 100. These proportions are gathered from measurements taken
from an.authenticated skeleton of each species, as the limits of the tail are difficult
of determination in Museum skins. I t was once thought that the species might be
recognised by differences in the size of the external ear, but I am doubtful that any
reliance can be placed on this character. Jf. pentadactyla is also at once recognised
from Jf. javanica by its broader and more conical head and less pointed muzzle,
in which respects Jf. aurita more or less resembles it, whereas the head of
M. javanica is very narrow, and with a longer interval between the eye and the
nose than in the other species.
To summarise the characters: Jf. pentadactyla is known by its heavy body;
by its tail which is broad at the base, tapering gradually to a point, and equalling
the length of the head and the trunk; by its large light olive-brown scales, of
which there are only from 11 to 13 longitudinal rows on the trunk and a mesial
line of 14 on the tail; and by its powerful fore claws, the centre one of which
is somewhat more than twice as long as the corresponding claw of the hinder
extremity.
Jf. aurita is distinguished from Jf. pentadactyla by its less heavy body; by
its rather shorter tail which has less basal breadth than Jf. pentadactyla ; by its
smaller and darker brown, almost black scales in the adult, which are more numerous,
there being from 15 to 18 longitudinal rows on the trunk, 17 rows being the
normal number, and 16 to 20 caudal plates in the mesial line; and by its strong
fore claws, the middle one of which is not quite twice as long as the corresponding
claw on the hind foot.
Jf. jmcmica is recognised by its body being longer and more attenuated than in
the twb foregoing species; by its narrower and more tapered tail; by its longer,
more foliaceous and darker olive-brown scales, of which there are 19 longitudinal
rows on the trunk, and as many as 30 along the mesial line of the tail; and by the
claws of the fore feet being not nearly so long as in Jf. aurita3 and being but little
in excess of the claws of the hind feet.
The variation in the number of longitudinal rows, more especially in the
case of Jf. aurita, appears to be due to one or other of two causes. When 17 rows
of scales occur, these structures are arranged in perfect longitudinal series, and
increase in size from the central dorsal row to the line of scales occupying the
middle of the side, but as the lines are traced downwards to the belly they decrease
in size, and the last row is occasionally reduced to a line of three or four small,
almost aborted scales on each side, whereas in well-formed individuals this terminal
row is a reduction of the preceding row in the same ratio of diminution which
characterises the rows preceding it. In those instances in which the lowest row of
scales is more or less aborted, one row may be entirely lost on one side of the
animal, thus giving rise to 16 longitudinal rows, while in other examples both may
be suppressed, thus reducing the total of the longitudinal rows to 15. When the
number of longitudinal rows is* in excess of 17, it appears to be due, not to the
development of a fresh series of independent structures, but, as in the case of ‘the
multiplication of the normal number of scales in some reptiles, to be attributable
to the division of the scales of either one or more of the normal series of longitudinal
lines. When this occurs, the symmetry of longitudinal distribution is interfered
with, and difficulty is experienced in tracing the lines. I t usually takes place in one
or other of the lateral rows, but a similar division of the head scales is not unfre-
quent, and in such instances the scales are smaller than in an animal with an undivided
series. In all Asiatic species of Manis there are only five longitudinal rows
of scales on the upper surface of the tail, the outermost row by its lower half entering
into the formation of the under surface of the tail, which has three longitudinal
rows of scales internal to these halves of the dorsal row. These ventral rows are
also frequently subject to division.
With regard to some general characters: In the young state in all the
species, the three or four most inferior rows of scales on the sides of the body are
generally keeled, as are also the scales on the hind leg, but more so in Jf.
javanica than in the other species, and in Jf. aurita than in Jf. pentadactyla. This
keeling, however, is of variable intensity in individuals of the same species, and
in the Troian and in the Himalo-Chinese forms it frequently disappears with age, as
the direct result of abrasion; but in adults of Jf. javamca it is always more or less
present, so that it would appear that the habits of the animal are somewhat different
from those of the two previous ant-eaters. This supposition is also supported by the
circumstance that its scales, instead of having their edges regularly worn off, as in
Jf. pentadactyla and Jf. aurita, are generally chipped and broken. This, however,
may be due to the more loose manner in which the scales are set on the body compared
with the compact overlapping in the other two species; but this very laxity of
arrangement of itself would suggest a difference of habit which the attenuated head
and much longer muzzle as compared with Jf. pentadactyla and Jf. au/rita would
seem to render probable. The scales of the tail of all the species, but more
especially of Jf. crnrita, show a tendency to form an obtuse ridge or keel, and this
is sometimes continued for a short way on to the back, but in other individuals of
the same species this character is obscure or altogether absent. The fine striae that
mark the scales, and which are most prominent in Jf. pentadactyla, are nearly all