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Show 1892.] SPECIES OF T H E HYRACOIDEA. 57 A. Dorsal spot wholly black P. capensis, shoana. B. Dorsal spot whitish, yellowish, or orange, a. Spot comparatively small, roughly oval in shape. a1. Hairs of spot, or at least the central ones, wholly yellow. P. syriaca, pallida. b1. Hairs of spot with dark bases and generally black tips. P. ruficeps, abyssinica. b. Spot elongate, linear. c1. Hairs pale coloured to their bases. * a2. Spot orange or cinnamon P.valida. b2. Spot pale yellow or whitish. P. brucei, bocagei, latastei, welwitschii, and arborea. d1. Hairs black at base, white terminally P. dorsalis. The central part of the dorsal gland is very commonly quite naked, notably in P. dorsalis, where the naked part is two or three inches long, and about half an inch broad. Owing, however, to the way in which the hairs round the naked part converge towards each other, this fact is very seldom observable without separating the hairs, but occasionally in old specimens the naked skin is clearly visible from above. The distinctions given above between the different sorts of spots are by no means to be taken au pied de la lettre for every specimen examined, many of the groups passing quite imperceptibly into each other, while in some species the spot itself varies so much as to be not easily definable. As to the geographical distribution of the different species the accompanying sketch-map (see p. 58) will show more clearly than any amount of description where the different forms are found, and will be a guide to anyone wishing to know what species may be expected to occur in any given locality, It may, however, be just noted that while many places have only one species known from them, most have two, and that these are almost invariably one of the hypsodont (Procavia) and one of the brachyodont (Dendrohyrax and Heterohyrax) groups. Thus in N. Abyssinia we have P. brucei and abyssinica, in Shoa P. brucei and shoana, in Angola P. bocagei and welwitschii, and in S. Africa P. arborea and capensis. The two tables exhibited (see pp. 59, 60) show respectively (1) the basal lengths1 of considerable series of specimens of each species taken at as many age-stages as possible, and (2) (a) the breadth of rn\ (b) the height of m3, measured as already described, and (c) the horizontal length of p\ It is to be hoped that, without a more formal synopsis, which at present I hardly feel capable of drawing up, these measurements, combined with the rough synopsis of the dorsal spots just given, will enable anyone to determine specimens without much difficulty. 1 Basion to gnathion. |
