In the foregoing examples of the species, the skulls of M. pentadactyla,
M. mrita, and M. javctnica measured in extreme length, respectively, 4’45 inches,
3‘45 inches, and 4 inches.
The skull of an undoubted example of the common ant-eater of India, M. pentadactyla
(Plate XXTV, figs. 1 and 2) sent to me alive from Chota Nagpur by
Colonel Dalton, C.S.I., is markedly distinct from either M. aurita or M. javmica,
from both of which it differs in the greater relative breadth of its occipito-parietal
region as compared with the facial portion, which is more abruptly and regularly
tapered than in either of these species, and this is not, as might be supposed, attributable
to youth, as the skull is fully adult. When viewed from above, the
cranium does not exhibit the marked orbital concavity in the outline which
distinguishes the skulls of these two species, and, moreover, the premaxillaries,
which in both of them are widely apart from the frontal, generally touch the latter
bone in M. pentadactyla. The zygomatic arch of the Indian form is only, as a
rule, partially defined, and I have never observed a specimen in which it was entire,
although at the same time it is probable that it may be so in old animals.
The skull of M. aurita (figs. 3 and 4)* is distinguished from the skull of the
foregoing species by a greater fullness in the facial region immediately anterior to
the orbit and by a proportionally narrower occipito-parietal area than in M. pentadactyla.
The nasal suture in Himalayan skulls is generally more rounded than in
those from Eastern China and Formosa, in which the nasals meet, as a rule,
in a point, but the character of this suture is most variable even in individuals
from the same region, and in Yunnan skulls the suture is either straight or
rounded. The skulls from Eastern China exactly agree in form with skulls from
Darjeeling and from Western Yunnan, but it is noteworthy that the majority
of the skulls sent by Swinhoe to the British Museum are not fully adult, and
that the species attains to a much larger size than any of the animals from
which these skulls have been extracted. Notwithstanding,—and this is a remarkable
circumstance,—these comparatively young skulls, in a small percentage, form
a distinct zygomatic arch by the complete union of the zygomatic processes of the
superior ma.-yilla. and squamosal to a considerable degree of thickness. That these
slmUs are yet young is shown by the condition of their sutures, so that the
formation of a zygomatic arch is not explicable by an overgrowth or undue ossific
tendency after adult age had been reached; and it is interesting to observe that we
do not find associated with this zygomatic arch any variation in the external
characters of these ant-eaters from Eastern China by which they can be distinguished
from M. aurita, Hodgson.
The skull of M. jmardca (figs. 5 and 6) is at once distinguished from the
skulls of the two foregoing species by its very narrow and elongated character,
and in these respects it finds its equivalent in the skulls of M. leptura
(fig. 7), and M. leucura (fig. 8), which are in no way separable from it; and
4o place this beyond a doubt, I have figured the skull of a specimen of M.
javmica from Java, and alongside of it the two skulls of the types of these supposed
species. In external characters, also, these supposed species are the exact fellows of
M. jmamca.
As sufficient prominence has apparently not been given to the peculiar glandular
sac in the stomach of the members of this genus, I take the opportunity to describe
the stomach and the relation of the gland.
The stomach of Mmis aurita presents a well-marked, downwwardly concave
lesser curvature, the centre of which corresponds to the division-of the stomach
into two well-defined portions, the cardiac and the pyloric, the former of which
considerably surpasses the latter in capacity, and is distinguished from it by the
thinness of its muscular walls as compared with those of the pyloric section. The
pyloric orifice is situated at a much lower level than the opening of the oesophagus
into the stomach. On laying open the stomach the longitudinal folds of the
oesophagus are prolonged along the inner wall of the lesser curvature as far as
the base of the concavity. Erom this point the finer folds of the oesophagus are
replaced by a strong mucous fold which is continued along the lesser curvature
to near its end, where it suddenly enlarges into a rounded head which contracts
and fits into the pylorus as a plug. The folds of the oesophagus are also prolonged
on to the right half of the anterior wall of the cardiac cavity, but the remainder
of the inner wall of that sac is thrown into a dense mass of strongly convoluted
mucous folds or rugæ. The pyloric portion has a thinner mucous membrane
rtin.n the preceding, and is rough, almost tubercular, and nearly devoid
of convolutions, and the plug of its duodenal orifice is covered by tubercles almost
spinose. Situated on the greater curvature of the stomach, immediately opposite
to the oesophageal orifice, is a large glandular swelling marked internally by a wide
patulous orifice, which leads into a limited chamber in the glandular nodosity.
This appears to correspond to the structure which has been described by Bapp 1
as consisting of a series of glandular follicles, the ducts of which terminate in
a common orifice, and which has also been referred to by Professor Elower in his
lectures on the Organs of digestion of the mammalia.2 In the stomach are generally
to be found small stones and gravel.
In a gravid uterus of M. pentadactyla the foetus was developed in the right
horn, and the general form of the organ resulting from this circumstance was
similar to what obtains in the Mare, Tapir, Camel, and Dolphin when the foetus is
developed in the same horn. The lips of the os uteri externum were composed of
the free ends of a series of fine lamellar folds which lined the interval, three quarters
of an inch in length, between it and the os uteri internum. These folds in
their lamellar character resembled the folds which occur in the Cetacea, and are
described by Prof. Turner3 in his admirable account of the arrangement of the foetal
membranes of that group. The right horn of the uterus was enormously enlarged,
and was directly continuous with that portion of the cavity of the viscus which lay
between the opening into the right and left horns and the os uteri internum. The
1 Edentata, 1852, p. 16. * Medical Times and Gazette, vol. ii, 1872, No. 1170, p. 592.
s Trans. Roy. Soc. Ediu. vol. xxvi. 1871, p. 473.