§ 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, Sciurida and Leporida, 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 state, fig. 540, k, l, become

an even exterior, in the unexcited 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 ccxi". 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 Leporide 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

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.1

§ 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, r, 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.

which opens into a wide urethra about an inch from the end of the clitoris, the groove of which is continued from the urethra. The usual subordinate relations of urethral and vaginal canals are here reversed. The clitoris in Dasypus 6-cinctus is longer than in the 9-banded species, measuring nine lines in the unerect state: it is of a pointed form, covered with a leaden-coloured integument, and situated an inch anterior to the anus: the vulva is placed on an eminence. From this orifice the urogenital canal extends eight lines, receiving the vagina by a transverse semilunar slit, and being then continued for five lines further without any diminution of diameter, and terminating in the form of a cul-desac, into which the urethra opens by a very small orifice. In Das. Peba, the urogenital cavity is not separated by a corresponding contraction from the urinary bladder, but is a more direct continuation of it. In this Armadillo the uterus is undivided; it expands to the fundus, which again contracts to a point, the oviducts being continued from the sides of the fundus: in Dasypus 6-cinctus the uterus is triangular, the fundus expanding into slightly produced angles, from which the oviducts are continued. These, in both species, wind round the peritoneal capsules of the ovaries, become tortuous, and terminate by fimbriate expanded openings directed toward the ovary, which was subelongate and smooth in both the dissected specimens.

In the Ai (Bradypus tridactylus) the uterus is like that of Dasypus 6-cinctus, the oviducts being continued from the angles of the fundus: between the uterus and vagina there is as little distinction; and the elongate common canal communicates (in the young Sloth) by two apertures with a short and wide urogenital passage. The ovaria are smooth elliptic bodies, with a greater proportion of stroma than in multiparous Lissencephala: the oviducts, commencing by fimbriate apertures upon the anterior edge of the capsule, pursue a serpentine course in that peritoneal fold to the fundus uteri. The ovarian ligaments are continued each along the margin of a peritoneal fold upward to the diaphragm, and downward to an oval parovarium,' or remnant of unusual size-of the Wolffian body': the unobliterated termination of its duct opens, as in most Lissencephala, on each side the urogenital passage, here very short. In the Unau (Bradypus didactylus) the rudiment of an uterine septum appears as a longitudinal ridge from the inner surface of the anterior wall in the unimpregnated state: in this species, also, the utero-vaginal canal communicates in the virgin animal by two distinct orifices with the short urogenital tract, the outlet of