circular fibres. The lining is well organised, not deciduous: it is soft, and disposed in many irregular folds, but, when these are effaced, has a smooth surface: this is a distinct but delicate layer with minute pores, and is connected to the muscular coat by an abundant tissue, consisting of fine lamellæ stretched transversely between the muscular layer and the smooth membrane, the whole being of a pulpy consistence and highly vascular, especially in the impregnated state. The vagina are lined with a layer of epithelium, which is readily detachable, even from the middle cul-de-sac. The inner surface of the culs-de-sac in the Opossum is smooth, but in the lower part of the single cavity in the Kangaroo and Potoroo it presents a reticulate structure. The lining membrane in the lateral canals in all the genera is disposed in regular longitudinal folds, a disposition which characterises the true vagina in most. In the Kangaroo, as in the other Marsupialia, the lateral canals communicate with the common or urethro-sexual cavity without making a projection; but at the distance of three-fourths of an inch from their termination there is a sudden contraction, with a small valvular projection in each, fig. 538, n, n. By those who consider the cul-desac and lateral canals as a modification of the corpus uteri, these projections may be regarded as severally representing an os tincæ; but they do not exist in the Opossums and Petaurists, in which there is simply a contraction of the vaginal canals at the corresponding part; and in both these and the Kangaroo, the true uteri open in the characteristic valvular manner, d,d, without the slightest appearance of a gradual blending with the median cul-de-sac. The clitoris is situated in a preputial recess near the outlet of the urogenital passage: it is simple in those Marsupials that have a simple 'glans penis,' but is bifid in those which have the glans divided: and in the Opossum each division of the glans clitoridis' is grooved.

6

The marsupial type is repeated in one of the rarer anomalies of the female organs in the Human species in

539

which not only the uterine cavities are distinct, but the 'os tincæ' of each opens into its own vagina, fig. 539.

§ 384. In Rodentia.-This order offers transitional steps from the foregoing type to the more common uterus bicornis,' with single os tincæ and vagina. In the Biscachia (Lagostomus trichodactylus) the two uteri are distinct, and each opens into a separate canal formed by a longitudinal septum continued about one-third down the vagina.' In the Capybara, Sciuride and Leporide, the two ora tinca of the separate uteri open into the fundus of a

common vagina, fig.540, h, i. In the Beaver there is one large prominence, like an 'os tincæ,' but the uteri terminate thereon by separate orifices. In Muride, the Aguti, the Paca, the two uteri blend into a short common cavity, with one opening into the vagina: they are connected together for some extent beyond the confluent cavities, or true corpus uteri.' The ovaries, which are elongated, subcompressed, and with

an even exterior, in the unexcited state, fig. 540, k, l, become botryoidal when the ovisacs are developed with ripe ova, fig. 772, A, a, a'.

In the Beaver the 'pavilions' are small and simple: upon these the oviducts are obliquely folded; the uteri are long, straight, and of uniform slender diameter when unimpregnated. The os tincæ is followed by a series of irregular flat processes, which project from the fore part of the vagina, gradually becoming smaller. The urethra communicates with the vagina near its distal end: the clitoris projects from a notch just beyond the urethra; and in front of the clitoris is the wide aperture common to the two large preputial or castor' bags: there are also smaller lobulated masses beyond the bags. In the Rabbit the aperture of the pavilion, ib. b', is more fimbriate and plicate than in the Beaver: it is continued along the border of a shallow peritoneal capsule extending from the further side of the ovary to the border of the broad ligament. From the ovary the remnant of the ligament of the primordial kidney ascends to the diaphragm. The oviduct,

1 ccx". p. 177.

ib. c, c', passes outward a short way beyond the ovary, then suddenly bends back toward the uterus, f: it is unravelled in fig. 772, A. The natural disposition of the efferent canals in the unimpregnated state are shown in fig. 540. The uterine tubes, e, ƒ, are united for a short distance by areolar and serous tissue at g; but open separately into the vagina, as shown by the styles, h, i. The longitudinal and circular layers of the muscular coat are as well marked as in Marsupials; but the inner coat has a different and lower structure: it is more homogeneous, and adheres closely to the muscular coat: its inner surface is more or less wrinkled, and is minutely porous, the orifices being those of the irregular canals called 'utricular glands,' exuding fluid, and lined by the formified particles or cells,' which likewise adhere to the free surface of the uterine lining. This, when injected, presents a fine reticulate structure, with a similar disposition of the superficial capillaries. Near the distal end of the true vagina are two small semilunar folds, with their concavity directed toward the urogenital passage. This is long in Leporida and a few other Rodents: its commencement is indicated, where valvular limits are wanting, by the opening of the urethra, ib. d: it terminates close to the vent in all Rodents; and, in the Hare, on the same nude patch of skin on each side of which is the glandular bag, q. The preputium clitoridis' opens just within the verge of the urogenital outlet: the clitoris commences by two crura, and terminates by a flattened bifid glans. In the Capybara the urethra terminates close to the vulva, and a groove is continued to the preputium clitoridis, which projects externally. In many Rodents (Arvicola, Lagostomus, Bathyergus) the clitoris is perforated by the urethral canal. In the Squirrel the vulva is a longitudinal slit upon a conical prominence or peak:' in the Porcupine the vulva is a thick semilunar prominence, puckered up internally into longitudinal folds, and opening immediately below the vent. The urethra and preputium clitoridis are close

to the vaginal outlet.

6

6

The human uterus repeats, as an anomaly, the grade of concentrative development attained by those Rodents in which a short common cavity or corpus' intervenes between the cornua and the vagina, as in the instance, fig. 541, given by ARTHUR FARRE in his masterly Article On the Uterus and its Appendages.'

§ 385. In Insectivora.-In some of these Lissencephala, as in

1 CCXLVI". p. 680.

some Rodentia, the clitoris projects externally to the vulva, and

is perforated by the urethral canal.

541

The Mole, which exemplifies this structure, fig. 542, c, also shows a complete closure of the vaginal orifice in the virgin state, ib. 1,' the vulva afterwards, ib. 2, intervening, at n, between the clitoris, c, and the prominent vent, below the letter n. The canals, severally continued from these apertures, viz. rectum, vagina, and urethra, are all anterior to the pubic bones, consequently outside the

pelvis. There is no valvular or other distinction between the vagina and corpus uteri: a long, somewhat tortuous, subdepressed

542

<]

utero-vaginal canal extends into the abdomen to terminate in the cornua uteri: these are cylindrical tubes, and describe three abrupt curves, on quitting the corpus uteri, at right angles therewith. The ovaries are commonly found with a tuberculate exterior, and are inclosed in an almost complete peritoneal capsule. The oviduct pursues a wavy course along this capsule to the uterine horn.' The ovarian ligament, commencing near the diaphragm, descends external to the kidney, carrying before it a peritoneal fold. The uterine ligament is continued from the end of the cornu,' and runs along the posterior edge of a continuation of the same fold, or mesometry,' to the part answering to the abdominal ring in the male.

External parts, female Mole. LXIII".

6

The Shrews closely resemble the Moles in their female organs: there is the same absence of os tincæ and a corresponding length of utero-vaginal canal from which the cornua, fig. 389, u, arch away at a right angle. In the impregnated specimen figured, the commencing embryos were lodged in cæcal dilatations of the cornua. In the great-snouted Shrew (Rhynchocyon), the ovaria, fig. 543, x, are placed each near the orifice, o, of a large peritoneal capsule, bordered by the oviduct, t, which slightly enlarges towards the

1 According to LXIII". p. 1006.

543

uterus. This commences by a bifid expansion, and is continued without constriction or distinction into a wide vagina with interlocking transverse folds at its uterine half. In Tupaia the clitoris is long but is merely grooved, the groove being continued to the urethral opening just within the vulva. The uterine cornua are short. In the Hedgehog the clitoris projects from a prepuce into a urogenital passage of an inch in length, midway between the vulva and the urethra here a slight constriction marks the boundary of the proper vagina. This canal soon becomes rugous; the rugæ are nearly transverse, increasing in breadth, and interlocking near the os tincæ, which seems to terminate the series. The body of the uterus is about half an inch in length; the cornua not much more. The ovary is tuberculate and furrowed; its peritoneal capsule is large, with a small orifice near the termination of the oviduct in the uterus. The ovaria are large and clustered, and the uterine cornua long, in the multiparous Tenrec (Centetes); the vagina has the transverse alternating folds at the uterine half of the canal.

Female organs, Rhynchocyon, CXXXIV'.

In the Bats the uterus has two very short horns: the long corpus uteri opens by an os tincæ into the vagina: in Pteropus the vagina extends into a cul-de-sac beyond the os tincæ.

§ 386. In Bruta.-The absence of the valvular or mechanical limit between uterus and vagina, noticed in certain Insectivora, is an inferior character repeated in the present order of Lissencephala. In the Armadillos (Dasypus Peba, e.g.) the uterine walls gradually become thinner, the epithelium denser and smoother, and longitudinal furrows finally denote the vagina,

Of the two specimens of Centetes setosus transmitted to me by the Hon. W. R. Rawson, Treasurer of the Mauritius, one had brought forth twenty young: he had known an instance of twenty-two at a birth, the more usual number being twelve to eighteen. I added dissections of the fœtus to the Hunterian Series under the No. 3577, A, to show the close analogy in form and structure of the male and female organs at that period.