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Show 1886.] MR. R. LYDEKKER ON SCELIDOTHERIUM. 491 PLATE XLV. Fig. 1. Outer aspect of the right pelvic limb of Geococcyx californianus showing the third layer of deep muscles, with a dissecting-chain pulling the ambiens into view. Life size, by the author from his own dissections. 2. Outer aspect of pelvis and right pelvic limb of Geococcyx californianus. Designed to show the deep muscles of the region, and the bones have been slightly rotated from their normal positions in order to bring them into view. a. Vinculum between deep flexor and. flexor longus hallucis. Drawn by the author from his own dissections. 3. Description of three Species of Scelidotherium. By R. LYDEKKER, B.A., F.G.S., F.Z.S., &c. [Eeceived September 20, 1886.] (Plates XLVI.-XLIX.) In the ' Zoology of the Voyage of the Beagle,' published in 1840, Prof. Sir Richard Owen founded the genus Scelidotherium on the evidence of a considerable portion of the skeleton of a large megatherioid Edentate found by Darwin in the Pleistocene of Bahia Blanca, in Patagonia, and applied the specific name of leptocephalum. In the following year and in 1842, Lund published in the volumes of the Copenhagen Academy descriptions and figures of more or less imperfect remains of various allied animals from the Brazilian caves, all of which were eventually referred either to Owen's genus or to the new genus Platyonyx, no less than seven new specific names being applied to these specimens. In 1850 the late Prof. P. Gervais published, in the results of Castelnau's Voyage (' Mammiferes fossiles de l'Amerique meridionale'), a description and figure of a skull from Buenos Ayres which he referred to the type species of Scelidotherium, and also of a second one from Tarija in Bolivia, which he did not name specifically but thought might be a new species. In 1857 Sir Richard Owen published a second memoir in the 'Philosophical Transactions,' in which he described and figured two skulls brought over in 1854 by Bravard from the Pleistocene of the Argentine Republic, both of which he referred to the type species. An important notice of the group was contributed by Dr. H . Burmeister, of Buenos Ayres, in his ( Description Physique de la Republique Argentine' x (1879), where he described a skeleton which he likewise referred to the type species, and also gave reasons for adopting Lund's genus Platyonyx for some of the allied forms. In 1880 Messrs. H . Gervais and Ameghino, in a memoir published under the title of ' Mammiferes fossiles de l'Amerique me'ridionale,' gave a synopsis of all the previously named species of Scelidotherium and Platyonyx, and applied the new specific name of S. tarijense to the above-mentioned skull from Bolivia, figured by P. Gervais ; and also founded a second 1 Vol. i. part iii. pp. 322-345, pi. xiv. There is no copy of the Atlas in any of the London libraries. |