mencement of the rectal portion, the lower half of which is thrown into longitudinal
folds.
In the duodenal sac, there are two patches (Eig. 3) resembling groups of
racemose glands. The whole of the smooth portion of the small intestine is covered,
both over the mesenteric attachment and opposite to it, with small orifices marking
the position of solitary follicular glands. Six inches from the vent the character of
the mucous membrane entirely and suddenly changes, the line of separation being
clearly indicated in the different character of the two membranes: the rectal portion
is coarse and more yellow in color, and the pigment of the external skin is prolonged
upwards except in the last 2 inches. I t is also thrown into strong longitudinal
folds, which are marked, here and there, by small openings leading into pits which
run forwards along the mucous membrane of the tube. There are also three or four
small circular openings which appear to be gland orifices.
In a young individual about 4^ feet, five glands (Eig. 5), each about the size
of a small bean, lie over the course of the mesenteric artery and are in close contact
with the pancreas and on a level with the intestinal orifice of the ductus communis
choledochus. A gland (Eig. 11, g), somewhat globular in form, and with a diameter
of 2 inches, occurs in close contact with the glands on the origin of the mesentery,
and reaches also to the mesocsecum, and is closely attached to the end of the small
intestine. I t so occupies the origin of the mesentery that that membrane radiates
from its lower margin, and nearly all the mesenteric veins converge to it and unite
in its centre. I t is also traversed by a branch of the mesenteric artery. The
gland, however, consists of two well-marked portions; one traversed by the vessels,
and another eccentric to them and lobulated. The first portion has a dark olive-
brown colour, and is soft and of one consistence throughout, while the other has
a pale pinkish yellow matrix through which a cartilaginous-like substance of a
bluish tint is interspersed.
The stomach of the Platanista is so largely infested with the parasite determined
by Cobbold1 to be Ascaris simplex that no sooner does the animal die
than they crawl in numbers out of its mouth. They are chiefly confined to the
stomach, but extend to the intestines.
The small intestine is the abode of another parasite, which Dr. Cobbold has
named Distoma andersoni.2
Pancreas.— PI. XXVI, fig. 5.)—This gland lies in'the bend formed by the third
sac of the stomach and the duodenum, above the ductus communis choledochus,
and at no great distance from the large gland (Eig. 11) that occurs at the union of
the large and small intestines, and with which it is intimately connected, as the
large vein traversing the latter passes directly through the upper division of the
pancreas, and is so large that a probe, fully a quarter of an inch in diameter, can be
passed along the vessel from one gland to the other in a young animal. In the
same individual the gland measures 2'50 inches in length, with a maximum breadth
of 2 inches and a thickness of about O'50 inch. The general characters of the
1 Proc. Zool. Soc., 1876, p. 297. * Joum. Linn. Soc., vol. xiii, p. 35, PI. x, fig. 3.
ductus communis choledochus which passes in front of the gland, I have already
described..
Spleen.—(PI. XXXVI, figs. 8 and 9.)—This gland in Platanista appears to be
rather small, as in the adult it measured only 3*50 inches in extreme length by 2'25
inches in breadth. I t is irregular in shape, and very unlike the well-formed spleen
of Orcella. I t is much compressed from side to side, and externally it is marked
by a series of lobular projections. In the adult, the course of the vessels along the
free border is remarkable, owing, to the existence of large dilatations (Eig. 9) into
which many crescentic orifices open, and another such sac occurred on the side of
the gland. These sacs, or dilatations, were filled with a grumous substance in the
fresh state which I had not the opportunity to examine microscopically. The walls
of the sacs were lined with a serous membrane, and, in a few instances, short bands
like cordte tendmece stretched across from one wall to the other in connection with
the orifices opening from the spleen into the sac. These orifices were of various
sizes, some being as minute as a pin’s point* while others were fully 0T2 inch in
diameter. Their margins had a free fold of membrane almost valvular, and. in some
instances an orifice so protected was found at once to divide into smaller but similar
openings. The largest sac had a capacity of 2 inches in length by O'7 5 inch in
breadth. Structurally both appear to be dilatations of the veins.
Liver.—Platanista agrees with other Cetacea in the simplicity of its hepatic
organ ; lobules and clefts being conspicuous by their absence. As the drawing
shows (PI. XXVI, fig. 10), it is almost transversely oval in figure, and very thick in
proportion. The position of the umbilical fissure which is shallow, the median pit for
the hepatic vessels, the inferior course of the wide vena cava, and the deficiency of
a gall bladder, all simulate what obtains in the majority of Whales. An examination
of the hepatic vessels showed no signs of a rete mirabile surrounding them, which,
as I have noted, obtains in the short-headed dolphin Orcella. The hepatic tissue
itself is firm; but otherwise presents no characteristic feature.
In the hepatic ducts of the Platanista are occasionally found immense numbers
of a small brilliantly coloured fluke, Distoma campula, Cobbold.1
Ploio-hole: its cavity, pads, and sacs.—The blow-hole (PI. XXXII, fig. 4, b) is a
longitudinal slit, about 2 inches in length, usually a little to the left of the mesial
line. In the longitudinal section of the skull, it is seen to be directed downwards
and slightly backwards and outwards. At 1*20 inch from the surface it becomes funnel
shaped, with a quadrangular outline in transverse section. This portion at its base
has a longitudinal diameter of O'40 inch, and in this locality the orifice of each
nostril is placed, and protected by rounded firm pads, which effectually close it.
In general appearance (PI. XXVII, fig. 1) it differs materially from the
blow-hole in other Cetacea, inasmuch as the antero-posterior direction of the exterior
orifice and the presence of the great lateral crests of the maxillary bones suggest a
restriction of the aperture and passage. I t is true that the spiracular cavity and nasal
sacs are not capacious; nevertheless, their .likeness to those of allied families is not
1 Joum. Linn. Soc., vol. xiii, p. 35, PI. x, fig. 3.
i 3