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Show 1882.] MR. W. A. FORBES ON THE GRE4T ANTEATER. 299 opportunity of verifying, this median septum is developed along the proximal (uterine) part of the vagina, instead of the distal (external) as in Myrmecophaga1. As Pouchet, though describing the two apertures, does not mention any median septum, it is possible that this vaginal septum may disappear, as there seems to be good reason for supposing that it does in Elephas indicus, in the gravid state. The penis in Myrmecophaya is so small that during coitus it is, I expect, entirely contained in the urino-genital tube, and does not enter the vagina, as is also the case in Elephas; the disappearance of the vaginal septum can therefore hardly be due, in this species at least, to the non-viryin condition of any particular female. 4. As regards other points, I may mention that the external and internal iliac arteries come off separately, as in many other mammals2, there being no common iliac arteries. As in Manis tridentata as described by Rapp3, the chevron bones in the tail contain a curious caudal rete mirabile, composed of both venous and arterial elements, which completely surrounds, as in a sheath, a central artery of large size, which is the direct continuation onwards of the abdominal aorta, and gives off here no branches at all to the rete. The arterial elements of this rete are derived from several small trunks on each side, which arise from the caudal artery beyond the origin of the internal iliacs, and then break up into a number of more or less parallel, rarely anastomosing, branches, mixed up with which are similar venous trunks. A similar rete occurs in Tamandua, and also, as I am informed by Prof. Flower, in the Spider Monkeys of the genus Ateles. The paired eyelids are very small, and hardly exist as special organs ; there are no eyelashes. The third eyelid, on the other hand, is very large and weli-developed. It contains a large cartilage of concavo-convex shape; on the internal surface of this eyelid, just below the inferior border of the contained cartilage, opens the minute aperture of the Harderian gland, which is very large, almost completely surrounding the orbit, and concealing the much more minute lachrymal gland. As described and figured by Pouchet, it consists of three chief lobes. As already suggested by Chatin, I have little doubt that it is the Harderian gland that has been described by Cuvier (Anat. Comp. 2me ed. iv. part 1, pp. 430, 431) and Owen (/. c. pl. xl. fig. 3 b) in Cycloturus as a salivary gland opening into the mouth. Clavicles are frequently supposed to be absent in the Great Ant- 1 A similar condition of things to that here described in the genus Myrmecophaga occurs sometimes, it may be observed, as a malformation, known as " vagina duplex et uterus simplex," in the human female, the vagina being more or less completely divided into two chambers by a median septum, and opening externally by two quite separate orifices. Cf. a paper by Dr. T. Matthews Duncan, Journ. Anat. Phys. i. pp. 269-274, and Dr. Morrison Watson's paper, " The Homology of the Sexual Organs illustrated by Comparative Anatomy and Pathologv," I. o. xiv. pp. 00-62. 2 Cf P. Z. S. 1881, p. 188. 3 L. c. p. 92. |