Chap. yi. 
AFFINITIES AND GENEALOGY. 
193 
°u the fore-arm is directed downwards or towards the 
"'list in the ordinary manner ; and in II. lar it is nearly 
G1 ’ect, with only a very slight forward inclination ; so 
that in this latter species it is in a transitional state. 
It can hardly be doubted that with most mammals the 
thickness of the hair and its direction on the back is 
"dapted to throw off the rain ; even the transverse hairs 
°n the fore-legs of a dog may serve for this end when he 
is coiled up asleep. Mr, Wallace remarks that the con- 
vergence of the hair towards the elbow on the arms 
of the oraug (whose habits he has so carefully studied) 
serves to throw off the rain, when, as is the custom 
°I this animal, the arms are bent, with the hands 
"lasped round a branch or over its own head. We 
should, however, bear in mind that the attitude of an 
a uiinal may perhaps be in part determined by the 
direction of the hair ; and not the direction of the hair 
h}’ the attitude. If the above explanation is correct in 
ihe case of the orang, the hair on our fore-arms offers a 
""lions record of our former state ; for no one supposes 
that it is now of any use in throwing off the rain, nor in 
° 1 "' present erect condition is it properly directed for this 
Purpose. 
It would, however, be rash to trust too much to the 
principle of adaptation in regard to the direction of the 
hair in man or his early progenitors ; for it is impossible 
to study the figures given by Eschrickt of the arrange- 
ment of the hair on the human foetus (this being the 
8a ®e as in the adult) and not agree with this excellent 
observer that other and more complex causes have 
intervened. The points of convergence seem to stand 
111 some relation to those points in the embryo which 
ai ' e last closed in during development. There appears, 
als °, to exist some relation between the arrangement 
VOL. I. 0 
