The ovaries, as in animals still in the breeding period of life, are tuber-culated or nodular from the presence on their exterior of Graafian follicles with ova nearly mature; they are seen to be attached to the infundibular fimbriate opening of the Fallopian tubes on either side by one of the fimbriae of that opening, the so-called tubo-ovarian ligament, which secures that an ovum on escaping from its Graafian follicle shall readily find its way into the oviduct. The ligaments and peritoneal laminae passing from the opening of the oviduct and from the ovary to the proximal end of the uterus cause the oviduct to take a very contorted course. In some mammals, e.g. Talpa, Cants, Ursus, Meles, the peritoneal laminae, which here form only a widely open capsule for the ovary and infundibulum, coalesce and form an all but completely closed pouch in which ovary and opening of oviduct are both enclosed, so that an escape of an ovum into the peritoneal cavity becomes nearly impossible except through the small orifice near the uterine cornu where the interior of the pouch communicates with the peritoneal cavity.
In the two carnivora last specified, even the small orifice thus left is frequently filled up by a hernia-like protrusion into it of one of the fimbriae of the infundibulum; and the ovary, a small portion of which is usually to be seen at that orifice, is thus cut off from view and from access to the peritoneal cavity. In some other Carnivora (Lutra and Mustela), at least in the young state, this orifice appears to be entirely closed by an overgrowth of peritoneal membrane.
a. The two uteri opening by distinct ora tincae into the single vagina.
Fig. 5. - Ovaries, Fallopian Tubes, Uteri, Vagina, Urogenital Canal, Rectum, and Organs in relation with the external openings of the two latter Canals from Female Rabbit (Lepus cuniculus). (One-half less than natural size.) b. Vagina laid open from behind in two parts of its length and showing a rudimentary septum on its anterior wall in its upper segment, and two semi-lunar folds in its lower and narrower segment.
c. Junction of urethra with vagina to form the urogenital canal, the upper half of which is laid open.
d. Entrance of ureters into bladder; the points of entrance are drawn a little higher up than they ought to be.
e. Junction of Fallopian tube with uterus of either side. From this point on the right a flat band, the homologue of the 'ligamentum rotundum' of anthropotomy and of the gubernaculum testis in the male, passes downwards and inwards, whilst from it and the Fallopian tube beyond it, that part of the 'broad ligament' known as 'ala vespertilionis' passes to the funnel-shaped opening of that tube.
f. Fimbriated and funnel-shaped opening of the Fallopian tube; the so-called 'Pavilion' or 'Infundibulum,' the mucous orifice looking into the peritoneal cavity inwards and backwards from the posterior aspect of the broad ligament.
g. Ovary, connected on the right side with the pavilion by the tubo-ovarian or 'infundibulo-ovarian' ligament, formed by the drawing out of the periphery of the pavilion, and on the left with the uterus of that side by the ovarian ligament. There are no fimbriae on the infundibulum of the Monotremata, and its outer periphery is almost entire in the placental genus Sus, but they are present, so far as is known, in all other Mammals.
h. Rectum, with one hydatid affixed to it.
i. Ano-preputial glands. Between the smaller of these glands and the rectum is seen part of the gland homologous with Cowper's gland and known as the gland of Bartholini.
j. One cms of the clitoris, with muscle in relation with it.
k. Rectum and external outlet of urogenital canal.
For descriptions and figures of the organs of the human subject corresponding with those described here, see Farre, Cyclopaedia of Anatomy and Physiology, vol. v. article 'Uterus and its Appendages.'
For the general homologies of the female generative organs, see Leuckart, Rathke, and Allen Thomson, as referred to above, p. 34.
For the vagina and uterus duplex as an abnormality in anthropotomy, see Dr. J. Matthews Duncan, Journal of Anat. and Physiol. May, 1867, p. 269.
The Palaeontological history of the order Rodentia may seem to put the affinity which has so often been alluded to as existing between them and the Ungulata into a clearer light than even the most detailed account of the anatomical resemblances which exist between the living representatives of the two groups under comparison. The most obvious, though perhaps also essentially the least important difficulty besetting such a comparison, is that which is based on the difference in size; but this is done away with by the discovery in American Miocene deposits of 'various small ruminant-like animals, some not larger than a Squirrel in size, to which the names Leptomeryx, Hypisodus, Hypertragulus, have been applied.' See Flower, Proc. Royal Institution, March 10, 1876. On the other hand, the discovery in the South American Pliocene deposit of the animal known as Mesotherium, which was a little larger than the Capybara, and has been supposed to link the Rodents and notably the Leporidae to the Perissodactyle type by many connecting peculiarities, whilst retaining itself so many of the characteristics of the Rodent order as to have induced Mr. Alston, P. Z. S. 1876, pp. 73, 74, to create for its reception a third suborder, that of Glires hebetidentati (see p. 44), equivalent to each of the two other suborders, those of Glires duplicidentati and Glires simplicidentati, into which Rodents may be divided, might seem to give as positive an illustration of the absence of any sharp circumscription in the delimitation of this group as can be asked for.