SECOXD day's sitting. 55 



is the nakedness of his skin. Whales and dolphins (Cetacea), 

 dugongs (Sirenia), and the hippopotamus are naked, and 

 this may be of advantage to them in gliding through the 

 water ; nor would it be injurious to them from the loss of 

 warmth, as the species which inhabit the colder regions are 

 protected by a thick layer of blubber, serving the same 

 purpose as the fur of seals and otters. Elephants and 

 rhinoceroses are almost hairless ; and as certain extinct 

 species which formerly lived under an arctic climate were 

 covered with long wool or hair, it would almost appear as 

 if the existing species of both genera had lost their hairy 

 coTering from exposure to heat. This appears the more 

 probable, as the elephants in India which live in cool and' 

 elevated districts are more hairy than those in the lowlands. 

 May we then infer that man became divested of hair from 

 having aboriginally inhabited some tropical land ? (Vol. i. 

 pp. 148, 149.) 



Homo. That question is very modestly put, my Lord ; 

 but how about the hair of the head ? 



Danvin. I was going to remark, my Lord, that " the 

 crown of the head " in man " offers a curious exception, for 

 at all times it must have been one of the most exposed 

 parts, yet it is thickly clothed with hair. In this respect, 

 man agrees with the great majority of quadrupeds, which 

 generally have their upper and exposed surfaces more 

 thickly clothed than the lower surface. Nevertheless, my 

 Lord, the fact that all the other members of the order 

 of Primates,* to which man belongs, although inhabit- 

 ing various hot regions, are well clothed with hair, gene- 

 rally thickest on the upper surface, is strongly opposed 



* The Primates, according to Linneeus, include man, mon ey, 

 lemur, and bat. 



