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Show 1900.] MAMMALS FROM S.W. ARABIA. 97 common throughout the Mammalia. Naturally every craniologist is more or less familiar with this fact, but in describing a new species on such material as the present it is necessary to emphasize the value of the size of the teeth as a criterion of species, irrespective of sex. Taking for comparison a good adult skull of a male Hamadryad from Abyssinia we find, in marked contrast to those given above, the following dimensions (in millim.):- Combined lengths of , * Total length 5 upper cheek- 4 posterior Length of of skull. teeth. lower cheek- last lower teeth. molar. d. Abyssinia .. 174 50-4 48 17-4 2 • Arabia 140 4L5 39-5 13-1 Such a difference in the size of the teeth evidently indicates specific distinction. In its general physiognomy the skull is, as might be expected, much less prognathous than that of the male of P. hamadryas, the orbits are similarly high and rounded, the facial ridges are less marked, the chin is much developed, and the shape of the coronoid is different, being more vertical and less slanted backwards. The complete measurements of the skull are as follows (in millim.) :- Greatest length (gnathion to occiput) 140, basal length (gnathion to basion) 98; zygomatic breadth 90; gnathion to lower edge of orbit 61 ; tip of nasals to orbit 32 ; orbits, width 24, height 22-5 ; brain-case, length from occiput to nasion 91, breadth on squamosals 67; interorbital breadth 46; palate length 57, breadth outside tooth-row 44; lower jaw, length from condyle 101, height at coronoid 50. In its external characters the skin may be described as follows: - Fur thin and scanty, rather wavy in texture across the back, the hairs across the shoulders but little lengthened beyond the rest. General colour dull greyish; the hairs on the crown and those of the middle line of the loins annulated, blackish with a buffy subterminal ring, those on the temples, sides of neck, shoulders, and flanks unannulated, dull grey. Hairs on the rump above the callosities with a strong rufous suffusion. Under surface and inner side of limbs practically naked. Hairs of arms and legs scanty, dull greyish, gradually passing into annulated black and whitish hairs on the hands and feet. Tail-hairs annulated above, pale greyish below, those at the tip forming a small dull whitish tuft. Measurements of a remade skin, approximate:- Head and body 590 mm., tail 410, hind foot 135. Considering the former extension of the genus into India, it was quite to be expected that the Arabian Baboon should prove different to that found on the African side of the Bed Sea. But it may be noted that the two Siwalik species, Papio subhimalayanus and P. falconeri, both have teeth as large as (or larger than) any of the African Baboons. P R O C . Z O O L . Soc-1900, N o . VII. 7 |
