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Show 1900.] HAIR-SLOPE IN CERTAIN MAMMALS. 677 same direction of slope of hair in this region as Man. From this I was led to suggest that the direction in question is due to pressure of the weight of the fore part of the body acting downwards and forwards, aird that the resultant of these two forces, in the cases of Carnivores and other animals accustomed to a " couchant " attitude when at rest, would tend to direct the slope of the hair away from the mauus on the extensor surface of this limb-segment. As a matter of fact this slope is found in nearly all Carnivores, wild and domesticated, in which the hair is short enough to allow of its observation. On the other hand, in most Ungulates one finds that the slope on this extensor surface does not present the reversed curl of hair found in Carnivores and Primates. This rule is far from universal: e. g., the Elk, Domestic Horse, and 4 Autelopes present on this limb-segment, over the distal fourth, a slope towards the radial border ; and further, 11 Antelopes and 20 Cervidae examined have a slope hardly differing from that of Carnivores (see subsequent remarks, p. 686). From this basis of fact 1 suggested that the hair-slope in Ungulates assumes this direction, which is more in accordance with the general slope of hair iu other regions of the limbs, and so differs from that of Primates and Carnivores, because of the attitude assumed by Ungulates when at rest. These animals so commonly rest with the extensor surface in question resting on the carpus and manus in flexion, in other words with the fore-limb doubled underneath the body, that any pressure downwards on this area of hair serves only to confirm its manus-wrard slope, there being no horizontal force acting with the vertical to produce a forward slide, as must always be the case in the "couchant" attitude of Carnivores. Following up this point, in ' Natural Science,' Nov. 1897, p. 357, I made a short note of the bearing of these facts on the doctrine of the non-inheritance of acquired characters. This matter has now been investigated somewhat further in a different region of the bodies of hair-clad mammals, namely, tbe frontal, nasal, aud premaxillary areas. I find among the different mammalian orders some singular divergences in the arrangement of this hairy surface. Here is a part of the body very much open to inspection, and one which from its prominent position must be subject to the action of tolerably constant external forces, differing necessarily in different forms, according to their environments. It is not possible to understand enough of the daily lives of many of the animals referred to below, but of some we may claim to know certain forces which cannot but act upon them in certain directions. A few of these will be considered later. The most common hair-covered mammals occur among Primates, Insectivores, Carnivores, Ungulates, Bodents, Marsupials, and Monotremes. The great majority of these conform to a certain general distribution and slope of the hair in this region of the head. This slope ordinarily commences in the premaxillary area just above the |