26 
THE DESCENT OF MAN. 
Part. I. 
the soles of the feet are quite naked, like the inferior 
surfaces of all four extremities in most of the lower 
animals. As this can hardly be an accidental coinci- 
dence, we must consider the woolly covering of the 
foetus to be the rudimental representative of the first 
permanent coat of hair in those mammals which are 
born hairy. This representation is much more com- 
plete, in accordance with the usual law of embryological 
development, than that afforded by the straggling hairs 
on the body of the adult. 
It appears as if the posterior molar or wisdom-teeth 
were tending to become rudimentary in the more civi- 
lised races of man. These teeth are rather smaller 
than the other molars, as is likewise the case with the 
corresponding teeth in the chimpanzee and orang ; and 
they have only two separate fangs. They do not cut 
through the gums till about the seventeenth year, and 
I am assured by dentists that they are much more 
liable to decay, and are earlier lost, than the other 
teeth. It is also remarkable that they are much more 
liable to vary both in structure and in the period of 
their development than the other teeth. 31 In the 
Melanian races, on the other hand, the wisdom-teeth 
are usually furnished with three separate fangs, and 
are generally sound : they also differ from the other 
molars in size less than in the Caucasian races. 32 Prof. 
Schaaff hausen accounts for this difference between the 
races by “the posterior dental portion of the jaw being 
“ always shortened ” in those that are civilised, 33 and this 
shortening may, 1 presume, be safely attributed to civi- 
31 Dr. Webb, 4 Teetb in Man and the Anthropoid Apes,’ as quoted by 
Dr. C. Carter Blake in 4 Anthropological Review,’ July, 1867, p. 299. 
32 Owen, ‘Anatomy of Vertebrates,’ vol. iii. pp. 320, 321, and 325. 
33 4 On the Primitive Form of the Skull,’ Eng. translat. in 4 Anthro- 
pological Review,’ Oct. 1868, p. 426. 
