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Show 1885.] DR. ST. G. MIVART ON THE ARCTOIDEA. 375 well as also a well-developed talon, which may be minutely tricuspid. The second lower true molar is a small rounded tooth, the grinding surface of which presents a median depression surrounded by a low wall. The brainx (which has been described and figured by the late Professor Garrod) presents the peculiarity of the hippocampal gyrus rising to the surface on either side of the great longitudinal fissure, and so making its very distinct Ursine lozenge incomplete behind. The callous marginal and crucial sulci unite, as also do the parietal aud sagittal gyri at the posterior upper angle of the cerebrum. Ictonyx2.-In colour and markings, as well as in the odour of the secretion of its anal glands, the one or two species which form this genus resemble the Skunks; so much so, that did they inhabit the same region, and were they devoid of an offensive secretion, they would certainly be said to mimic the Skunks. They differ greatly from the Skunks, however, in the form of the teeth, in which they approximate to the Weasels. The head is conical, with a pointed nose, marked at the tip with a median groove. The ears are rounded and hairy. The claws are long and pointed and not retractile. The hind foot is digitigrade, with the hinder part of the sole hairy. The tail is long and covered with long hair. The body is elongated, the lines short. There are 15 dorsal, 5 lumbar, 2 sacral, and 23 caudal vertebrae. The dorsal region is almost the longest relatively, and the sacral region is the shortest of any Arctoid. The third phalanx of the third digit of the pes is also at its maximum of relative length, as is the breadth of the brain-case, the length of the lower molar series, and the length of the fourth upper premolar, the length of the spine being the standard of comparison. The cranium has the characters mentioned by Prof. Flower3, as also the following ones. The frontal postorbital processes are marked, but there are none from the malars. The zygomata do not arch strongly outwards. The size of the infraorbital foramen is moderate. The palate extends back but little behind the last molars. The mastoid processes are rather prominent, but do not descend to the level of the floor of the meatus auditorius externus. The stylo-mastoid foramina are very conspicuous, and the opening of the external auditory meatus is very large. The angle of the mandible resembles in form that of Meles. Molar formula = P. | M . \. The general form of the teeth is that which exists in Mustela \ but the first upper true molar is larger, and it is much wider than long and has five cusps. Two of these are the two external principal cusps, outside which is a single cusp developed from the 1 See I. c. p. 18 and P. Z. S. 1879, p. 307, figs. 1 and 2. 2 Or Zorilla. See Schreber, iii. p. 445, pi. 123; Buffon, xin. p. 289, pi. 41 ; Lichtenst. Berlin Abb. 1838, p. 281, pi. 2 ; Gray, Lond. Mag. i. p. 581 ; P. Z. S. 1865 p. 151, Cat. of Carniv. Brit. Mus. p. 139 ; De Blamville, Osteogr. Mustela ; Wagner, Suppl. ii. pp. 199 and (Rhabdogale) 219 ; P. Gervais, M a m m . ii. p. 115. 3 P. Z. S. 1869, p. 13, Rhabdogale. 4 See below, p. 378. |