from tlie central thickened area, and sparsely scattered, minute villi and folds like
the hare spots of the chorion generally. The blood-vessels of the chorion branch
dichotomously and do not' show any of the tortuosities which characterise the
chorion of the mare. A very few vessels, however, almost as fine as human hairs,
distributed over the allantoid portion of the amnion, are somewhat tortuous, but
in a moderate degree. I have traced these vessels into the arteries of the cord.
One of the dorsal surface bare spots situated 8 inches to the right of the funis
is distinguished from all the other smooth spots of the chorion by bearing a
shortly pedunculated solitary corpuscle. This spot has a diameter of 0'25 inch.
The corpuscle does not occupy the centre of the spot, but is placed to its left side,
(Plate XXXIV, fig. 4).
The membrana intermedia can be separated from the chorion and the amnion.
The attachment of the allantois to the membrana intermedia, and through it to
the chorion, differs from that of JBlatanista in this respect, that the allantois
adheres more to the ventral and posterior surface of the chorion, whereas, in
the former genus, it is attached from the posterior towards the dorsal surface. It
differs also in form from that genus, the portion opposite the funis being pyramidal,
and the continuation on either side of it being narrower and more tubular thn.-n in
Tlatanista, but in its linear extent it resembles the latter.
The corpuscles of the amnion are very much larger than in P. gangetica, but
have much the same distribution. Each corpuscle is white at its base, and many
of them have short peduncles, while others appear to have fallen off, leaving their
peduncles. Some of these bodies on the cord, in its last 3 inches, have peduncles
an inch in length, but they do not exceed four to six in number, the majority being
sessile. A few corpuscles also occur on the amnion, where it is reflected off the
allantois, but close to the margin of the latter, to the right of the funis, and on
the ventral aspect of the sac.
The allantois terminates 2 inches from the extremity of the right horn of the
chorion, and it extends about 2 inches beyond the bare spot corresponding to the
left Eallopian tube. I t has thus a length of about 36 inches in the chorion contracted
by preservation in spirit. At 7 inches from the left pole it has a breadth of
3 inches between the two points where it is reflected off the chorion, while opposite
the funis the same interval has a breadth of about 7 inches.
Microscopic structure o f the chorion.—In the partially injected chorion, its
rough surface presents a villous vascular appearance somewhat resembling that of
Tlatanista (Plate XXXVII, fig. 13), the villi, however, being shaggier and more unequal
in size. In a vertical section of the chorion from the gravid horn of the uterus
of Orcella, not injected (fig. 14), the inequality of the villous tufts is apparent.
In some places they are bud-like, low and closely set, at other spots a portion of the
membrane protrudes and throws forth long loops of arborescent vascularvilli, thus
giving rise to deep unequal intervals and to a pseudo-cotyledonary character. The
chorionic villi are freely covered by squamous epithelium, though in some spots I
could observe a modified cylindrical kind. The basement membrane is of the. usual
connective tissue, most delicate in nature, and with elongate and sub-circular nucleated
corpuscular bodies distributed in profusion throughout it. Here and there, long linear
rows of the fusiform cells appear, and predominate in encircling lines round the larger
sized blood-vessels, being well marked where these are seen cut transversely. The
opposite free allantoic surface of the chorion has a thin covering of large pavement
or tessellated epithelium, each cell of which sits loosely to its neighbour, and
all are abundantly granulated, or filled with refringent particles, simulating oil
granules.
Umbilical cord.—This is about 13 inches long,and describes a series of curves.
Besides the peduncular corpuscles which occur near its funis, the cord throughout
its extent is studded over, both in the intervals between the vessels and on the latter
themselves, with small glandular-like bodies which are covered by the investing
membrane of the cord. These are of two kinds; one, elongated ovoid bodies, half
white and half dark, or with almost black centres, and in this respect, as in their form
and general characters, they resemble the pedunculated bodies of the amnion. The
other bodies are much more numerous, and are either yellow globular masses or they
consist of a number of such masses aggregated together. The yellow bodies are
well-defined sacs (Plate XXXIV, fig. 8, y), with thick walls which do not collapse
when cut across and are most numerous in the loose areas betwixt the vessels.
Lymphatics o f cord.—Lying between the point of division of the umbilical
vessels and the'two veins there exists an oval, red, glandular body (Plate XXXIV,
fig- 9 ffl)’ almost a quarter of an inch in diameter. A fine reddish, wavy, moniliform
tube (fig. 9, m) enters this structure and leaves it at the opposite end. This red body
is a sac filled with a grumous substance, which under the microscope consists of a
multitude of very minute, variously sized round cells. These cells exhibit a black
speck-like nucleus or centre, and along with them are larger cells and a mass of
granules. The walls of the sac internally have a velvety appearance, from the fact
that they are covered over by a multitude of fine villous processes. Situated 0"‘75
below the red glandular body, and lying over the left umbilical vein at the point
where it reaches the chorion, a small sac occurs, 0ff*35 long. Its walls are very
delicate, colourless, and transparent, and the upper half of its extent is divided off
from the rest of the cavity by a very delicate septum, which has a slit in its centre,
but I cannot be decided as to this, because it is possible I may have ruptured the
septum in passing a needle into the larger cavity, before I became aware of the
existence of the septum. The presence of the septum is externally indicated by a
slight constriction of the sac, and the f ratal end of the secondary cavity rapidly
contracts and is prolonged upwards to the red glandular body as a fine tube, which
is with difficulty distinguished, as it has the same colour as the general substanee of
the cord (fig. 9, Ih). Another vessel of the same character passes out from the
opposite end of the primary canal of the sac, but I failed to trace it to its end.
A pedunculated structure (fig. 9, p), also evidently glandular, is closely associated
with the glandular body just described. In near proximity to it is another
moniliform tube the course of which I was not able to trace satisfactorily, but