With Figure 4.
The upper half of the bladder has been removed, and the cavity of the lower half, a, laid open from behind, as have been also the cavities of the Uterus masculinus, s. 'Organ of Weber,' s. Vesicula prostatica, b, and of the urogenital canal at d. The right crus penis has been cut through at l, as also the left, not seen in the figure of this Preparation; and the parts removed from their connection with the pelvis. A wire has been passed from the cavity of the bladder along the urethra behind the uterus masculi-nus, b, into the urogenital canal, d, and along this canal to its outlet in the glans penis. The rectum, c, has been displaced to the right from the mesial plane which it naturally occupies. The walls of the bladder have been turned outwards, and the orifices of the ureters appear consequently to lie upon its anterior instead of upon its under or posterior surface as in nature.
The uterus masculinus, b, is of colossal proportions in the .Leporidae, attaining in some cases an absolute length of as much as three inches. With the exception of the Koala, it has not been observed in any marsupial, the generative organs of which animals, however, resemble those of the Rabbit in some points, as, for example, in the absence of seminal vesicles. It bears here a striking resemblance to the upper part of the vagina of the female Rabbit, as shown at b in Fig. 5, p. 37, having a similar rudimentary septum developed upon its anterior wall. But the presence, not merely of a considerable interlacement of muscular fibres, but also of glandular structures in its walls, as also some other reasons, would seem to make it safer to consider this organ to represent at once both uterus and vagina. Its upper angles are slightly produced and project between the upper boundaries of the prostatic glands, hy and the cut short ends of the vasa de-ferentia. These projections, like the somewhat similarly drawn-out upper angles of the true human uterus, must be taken to represent the cornua uteri of the uterus duplex and uterus bicornis.
The organ is flanked on either side by three packets of tubular glands, two lettered h and i, and a third which, being placed between them and somewhat anteriorly, is not seen clearly in this figure. This last consists of three simple unbranched tubules, which, though said by Weber to be variable in presence, are yet usually to be found in the interval between the lower ends of the two packets, h and z, and open by three distinct orifices into the urethra, as stated by Martin St. Ange, Etude sur l'appareil reproducteur, p. 11, who calls them 'accessory prostates.' The larger of the two other packets of glands, h, is readily separable from its fellow of the opposite side, posteriorly as well as anteriorly; the smaller, i, interdigitates more or less intimately with its fellow on the posterior surface of this portion of the urethra, but, as in the human subject, the glandular elements of the prostate do not cross the middle line anteriorly. The characteristic concentrically laminated prostatic concretions are found in the tubuli of the smaller packet, though not in the larger; but it is in accordance with general usage to speak of both of these sets of glands as 'prostates,' the smaller as the 1 anterior ' and the larger as the 'posterior prostates.' The anterior prostate is divaricable into two lobes, each with a separate duct: the posterior has but a single duct: with, however, the three ducts from the accessory prostates there are six ducts opening into this portion of the urethra on either side.
In the adult Rabbit the vasa deferentia open by an unusual arrangement into the uterus masculinus about two lines from its orifice; in the embryo the normal arrangement exists whereby the uterus masculinus opens a little way above these ducts. The testes have been removed in this preparation, together with the greater part of the vasa deferentia, the cut ends of which are seen passing behind the upper angles of the uterus masculinus. The portion of the urogenital canal which is laid open at d corresponds to the portion known in anthropotomy as the 'membranous,' 'muscular,' or 'interfascial' portion, and as the 'isthmus urethrae.' Though longer relatively than in our own species, it has by no means the same relative preponderance which the homologous portion of the canal has in some other Rodents, as e.g. Arctomys, and in some Carnivora, e.g. Canis.
The wire which has been passed down the urogenital canal from the interior of the bladder projects from the orifice of the urethra, which in these animals, retromingent like other Rodents, has the shape of a vertical backwardly-looking slit. The Cowper's glands, j, organs found in all mammals except, so far as is known, Mustela and Delphinus, with capsules of voluntary muscular fibre and ducts leading into the commencement of the spongy part of the urethra, are seen on either side of the sinus urogeni-talis. On the left side we see at l, in the plane in which this canal passed under the pubic arch, one of the crura penis with the pubo-cavernosus and ischio-cavernosus muscles cut through and detached from that arch, and on the opposite side we see, at k, two ano-preputial glands, one much larger than the other, and a hairless area of integument, g, on to which the ducts of these glands open, and which is prolonged into the fold covering the glans penis. A similar arrangement to this exists in the Tenrec. Just below this area the anus opens at e. The rectum, c, has been displaced outwards and to the right so as to give an unimpeded view from behind of the organs just described.
At its upper part it carries, attached to its longitudinal muscular coat, two hydatids, the cystic stage (Cysticerctcs pisiformis) of Taenia serrata, which takes on its cestoid or 'strobile' form in the intestines of the Dog or Fox.
Fig. 4. - Bladder, Uterus masculinus, and Urogenital Canal from its commencement