1885.] DR. ST. 6. 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 sur- 

 face of which presents a median depression surrounded by a low wall. 



The brain ' (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 

 and sagittal gyri at the posterior upper angle of the cerebrum. 



Ictonyx '. — 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. Tlie 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. Flower ', 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 aud P. Z. S. 1879, p. .307, figs. 1 and 2. 



^ Or Zorilla. See Schreber, iii. p. 445, pi. 123 ; Buffon, xiii. p. 289, pi. 41 ; 

 Lichtenst. Berlin Abh. 1838, p. 281, pi. 2 ; Gray, Lond. Mag. i. p. 581 ; P. Z. S. 

 1865, p. 151, Cat. of Cariiiv. Brit. Mus. p. 139 ; De Blainville, Osteogr. Mustela ; 

 Wagner, Suppl. ii. pp. 199 and {Bhabdogale) 219 ; P. Gerva.i8, Mamm. ii. p. 115. 



3 P. Z. S. 1869, p. 13, Bhabdogcde. 



* See below, p. 378, 



25* 



