less pointed. I am disposed to believe that this male skull (No. 6, and Plate XXXIX,
fig. 1) is of the same species as the skull fig. 2 from the Hughli, which is only 2*25
inches shorter than the large skull from Chupra. By a comparison of the various
measurements of the skulls Nos. 1 and 6, it will be observed that the great differences
lie between the relative proportions of the snouts, which are decidedly longer
in all of these female skulls than in the males. Of course, there is the other alternative
that two or more species may exist, and that these males with small skulls
may be the males of a species of which the females are yet unknown, and that I
have never encountered the males of such large females as the specimen from Chupra.
The evidence before me, however, does not sanction such a conclusion, and until
further facts are adduced, there is no other course left but to regard the male as a
considerably smaller animal and having a shorter snout than the female, and that
individuals vary in size in different localities.
Respecting the probable size attained by this Cetacean genus, it would appear
that the Chupra female had arrived at her limit of growth. In the largest female
from the Hughli in the accompanying tables the epiphyses of the vertebral processes
are firmly united with the vertebrae, and very many, but not all, of those of the
bodies are completely anchylosed to the latter, so that she is fully adult. Taking
the ascertained size in the flesh of this animal and the length of its skull as our
guides, it seems probable that the aged Chupra female must have attained a length of
nearly 9'50 feet from the tip of its rostrum to the fork of its tail, whereas the length
of the largest male with quite as mature a skeleton and skull was scarcely 7 feet.
Microscopic structure of the skin.—The skin structurally differs little, if at all,
from what obtains in the generality of the Whale tribe. The anomalous shape of the
snout and the condition of the parts around the spout-hole, however, led me to
examine the dermal constituents, and I here record my observations.
The thickness of the skin, as in land animals,, varies according to region and
. other circumstances. Over the pectoral flippers, the skin is 5 millimetres thick, of
which the epidermic layer forms two-thirds of a millimetre, and is dark bluish-black
in section, the cutis being a clear white, of great consistence and sharply defined from
the underlying oily layer, which is 8 mm. thick and yellow in colour, and also
strongly fibrous. On a level with the dorsal fin, the oil disappears out of this
layer, which becomes like the one overlying it, only somewhat yellow. Over the
vertebrae, in front of the dorsal fin, this fibrous layer is T50 inch in breadth from
side to side and 2-25 inches in vertical thickness.
A piece of the cast-off, dried cuticle, when mounted in Canada-balsam and viewed
by transmitted light, to the naked eye and with a hand-lens, appears as a yellowish
or faintly brownish film, the darker tint marking fine parallel lines. Under a higher
power the linear arrangement is seen to be wavy (PI. XXXVI, fig. 1), the minute
linear folds dove-tailing and running into one another, here and there. They, and
likewise the lighter coloured intervening spaces, indeed the whole tissue, are speckled
uniformly with minute dots, viz., scdly nucleated epithelial cells containing an
abundance of dark pigment.
Vertical sections through the dermal and subcutaneous tissues of part of the
snoüt (Pl. XXXVI, figs. 2 and 3, and see also Pl. XXXI, fig. lh) demonstrate the
usual constituents, save the absence of sudoriparous and sebaceous hair glands.
The papillæ of the vertically descending epidermal layer are stout, and not quite
uniform in length, the shorter ones being rather conical, the thicker slightly club-
shaped, a few having bifid extremities. The corresponding ascending papillæ of
the corium have a copious capillary supply derived from the rather numerous bloodvessels
of the deeper tissues. Where the hair-like bristles have been cut through
obliquely (fig. 2 h,) in the sections made from the foetal specimen of Platmista,
their walls are thick, and surrounding them is a wide circular and dense fibrous
area, the outermost wavy elastic fibres of which mingle with those of the neighbouring
connective tissue. The superincumbent half of the fibro-vascular layer .of the corium
has but few traces of oil particles intermixed, but in its deeper half, the fatty
particles and oil globules preponderate, and are both very numerous and characteristic,
as large elliptical areas. In many of the larger-sized oil globules, bundles of
needle-shaped and stellate crystals present themselves. In this snout-section, the
fibres of the subcutaneous tissue, both strong and glistening, form often a lozengeshaped
mesh-work, and deeply become stouter, as bundles of broader bands interlace
freely and enclose in layers the fatty constituents above spoken of. Below the
blubbery layer comes a layer of ordinary connective tissue, the masses of striated
muscular fibres joining this again. .
Mouth.—On opening the mouth of JPlata/nista, its form is seen to be triangular,
the base of the figure being placed posteriorly. The upper lips have a
sharp edge and crescentic outline, the convexity looking inwards and downwards.
The anterior end of the upper lip is prolonged forwards to the external margin
of the alveolar line of the teeth of the snout, and its posterior end is under the
eye. The upper lips are not supported by bone, but consist of the strong fibrous
tissue that fills up the interspace between the maxillary laminæ, and the lower
limit of which extends from the preorbital process of the frontal to the side of
the dental portion of the superior maxilla opposite to the twenty-third tooth. The
lower lips are round, fleshy, and concave from before backwards, and are overlapped
by the sharp edge of the upper lips. The inner margin of the upper lip is devoid of
pigment, but the under lip has more or less the colour of the external skin. The
jaws are capable of great extension, opening at their tip, in a specimen nearly feet
long, to 13 inches, the distance between the angles of the mouth being 4 inches, the
anterior breadth being only 0*65 inch. The interior of the mouth and the palate
are quite smooth in the half-grown individual, but, in the adult, the sides of the
mouth from the angles are thrown into strong longitudinal folds which extend
back to the fauces. In the same individual the faucial region measures 2 50 inches
across and T75 inch in vertical capacity, which, however, is doubtless greatly
increased when the tongue is drawn down.
Tongue.—In this fluviatile dolphin, the lingual organ is well developed. I t is
firmly attached at its tip by a fold which rims forward to the symphysis of the lower
G 3