it had all the appearance of either terminating in the red glandular body or of being
connected in some way to the moniliform tube proceeding from it. The course of
this vessel in the opposite direction lay towards another transparent, but smaller
sac (fig. 9 lh*), lying somewhat nearer the chorion than the first mentioned and
larger sac.
The intimate relationship subsisting between all of these structures, glands,
moniliform vessels, pedunculated glands and sacs, and their close connection with
the vessels devoted to the nourishment of the foetus, suggest the likelihood that they
are important elements of a glandular system subservient to the vascular system of
the chorion, and that the sacs are analogous to lymphatic hearts.
Besides the arteries and urachus which have their usual relations, there is
another tubular cavity in the cord lying between the veins and the urachus, and
when the cord is cut across close to the abdominal wall two or more orifices may be
detected in the cut end leading into it. I t has a length of about 5 inches, and is of
considerable capacity, being in some parts fully half an inch in diameter. In some
parts of its course it is divided into secondary channels by septa or folds extending
from one wall to the other, and also from part to part of the same wall. The interspaces
between the blood-vessels consist of a loose membrane, indeed so loose that a
probe passes easily along the orifices as they become distended when the cord is cut
across at intervals. Yellow glandular sacs are common on these areas, but are not
numerous near the funis, and in fig. 9 they are seen in the upper part of the drawing
chiefly in the mesial line and on one side.
The veins and also the arteries of the cord communicate with one another,
and at about 10*25 inches in the case of the former and 10 inches in the latter, their
respective internal calibres are as 0"*20 to 0"*60. In the artery, the communication
is direct and is outwards from the smaller to the larger. But in the veins the channel
is first towards the foetus and then [backwards ; the orifice in the first vein forming
a kind of sac before the channel turns backwards to reach the other veins. In the
case of the arteries, the channel passes below the urachus from artery to artery. Below
this point, the larger artery presents a considerable dilatation of an elongated
character, and a number of large branches are given off from it and very many
small twigs. I t is then continued on to the right side, branching in its course.
The smaller artery does not show any dilatation, and passes to the left side of the
chorion. Only very small twigs are given off from the arteries prior to their inosculation.
The veins are dilated at intervals in their course prior to the inosculation
of the main trunks, but not to the same extent as in JPlatamsta. The vein from the
right side of the chorion, also like the artery, presents a great dilatation at the point
at which it lies alongside it, about an inch and a half below the anastomosis. But
no such enlargement occurs in the vein to the left side of the chorion which does not
receive so many branches as is the case with the vein of the right side.
Minute structure of the' ovarykSrbi transverse transparent slices of the ovary
of the foetus of Orcella brevirostris I found the cortical layer surrounding the
entire organ to be most numerously studded with ova (Plate XXXVII, fig. 10, o).
Quite at the peripheral margin these Graafian vesicles were most abundant,
causing the circumference to assume quite a granular character even to the naked
eye, and markedly so under a hand-lens.
In those parts of the section where it had not been made too thin, and where
consequently the relations of the tissues were least disturbed, it seemed as if the
follicles, just within the more uniform zonary margin, began to have a festooned
appearance, the festooned groups being arranged somewhat irregularly into less
or more wedge-shaped masses ; these latter, occasionally composed of parallel lines,
tending inwards in a wedge-shaped manner, some terminating in single narrow
centrally directed lines, others joining and approaching archedly the angle of
the neighbouring wedge. Thus the entire superficial surface of the ovary, with
a diameter of over a quarter of an inch, has a surrounding ovigerous band about
0"*08 deep : the band thinning inwards with conical pillars sparsely connected by
arching lines of scattered Graafian follicles.
The fibro-nucleate character of the attached border of the ovary is more pronounced
than is the general stroma of the organ; the wavy nucleated nature of
the connective tissue of the medullary stroma is notwithstanding very apparent,
especially where encircling blood-vessels, and here and there it leaves open
spaces.
On examination under higher powers of the microscope, the structure of thè
Graafian vesicles could be tolerably well made out in some places, much less so in
others. In the best examples, the band of cells constituting the proligerous disc
(itunica granulosa) was very clear and distinct, and it encompassed closely but
loosely the much darker and denser vitellus, in the midst of which, but only
in very few, a germinal vesicle was appreciable, but whose germinal spot was by
no means definitely made out.
I further investigated the ovary of the gravid female, one section of which,
taken through the corpus luteum, I show in Plate XXXVII, fig. 11.
The stroma of this specimen (s) was almost entirely composed of comparatively
large-sized oval and hexagonal nucleated cells agglutinated together by delicate
nucleo-granular and fibrillated connective tissue, fig. 11 A. The stout outer fibrous
true coat resolved itself very distinctly from these. Towards the periphery, immediately
beneath the outer envelopes, but also more sparsely scattered through the
medullary part of the ovary, were ova in various stages of development. Some of
the Graafian vesicles were empty, the ova having escaped. In other ova present,
cell proliferation, germinal vesicle, and nucleus were distinctly manifest.
Besides the cellular nature of the stroma, the most interesting features in this
ovary, and shown in figure 11, were the remnant of a corpus luteum and the pale
central bands. The follicle containing the corpus luteum (cl) lay just within the
tunica albuginea, and was about the size of a mustard-seed, of a triangular shape,
the apex pointing inwards, and the vesicle retaining the lining cellular envelope
(membrana granulosa). There was a narrow open space to one side, and the remainder
of the cavity was occupied by the yellow body composed of corpuscular and