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Show 1881.] VAGINAL APPARATUS IN THE MACROPODID.E. 995 body. The sections of the genital gland were compared with sections of the ovary and testes of the young Rabbit (22-30 days)1; and the structure was found to resemble the former rather than the latter, although the state of preservation of our specimen is not good enough to allow us to be certain. More satisfactory evidence is afforded by the fact that two oblique folds meeting behind are situated on the ventral abdominal wall, enclosing a rudimentary pouch. As we are not aware that any such rudiment is found in the male, we conclude that the specimen is a female. Our sections show the Miillerian ducts opening anteriorly into the abdominal cavity. They pass backward along the margin of the Wolffian body by the side of the Wolffian ducts ; as these two ducts Fig. 4. WB. a. Sketch of urogenital organs of young Macropus rufus, from the left ventrolateral aspect, magnified. b. Diagram showing the arrangement of the ducts: Bl, bladder; M. d, Miillerian duct; ov, ovary; u.g, urogenital sinus; Mr, ureter; W. B, Wolffian body; W. d, Wolffian duct. pass backward they approach the middle line, the Miillerian duct being the inner, the Wolffian duct the outer of the two, while the ureters are external to the Wolffian ducts. Thus at first the Miillerian ducts of the two sides converge; they do not meet, however, the distance between them at their nearest point is three times the diameter of the Miillerian duct. After converging, the ducts pass directly outward, each accompanied by the Wolffian duct, to the outer region of the mass of mesoblast, in which all three sets of ducts (Miillerian, Wolffian, and ureters) are here embedded. They then turn backward again, while tbe ureters pass inward to the bladder. From this point the Miillerian and Wolffian ducts again converge. Posteriorly 1 These sections were kindly lent us by Mr. F. M. Balfour. 64* |