20 Tfu Descent uf Man. Part I 



teen assured by a surgeon to a hospital for children, have theil 

 backs covered by rather long siljiy hairs ; and such cases pro- 

 bably come under the same headl 



It appears as ;f the posterior molar or wisdom-teeth were 

 tending to become rudimentary in the more civilisud races of 

 man. These teeth are rather smaller than the other molars, as 

 is likewise the case with the corresponding teeth in the chim- 

 panzee and orang ; and they have only two separate fangs. 

 They do not cut through the gums till about the seventeenth 

 year, and I have been assured that they are much more liable to 

 decay, and are earlier lost than the other teeth ; but this is denied 

 by some eminent dentists. They are also much more liable to 

 vary, both in structure and in the period of their development, 

 than the other teeth.*" 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." 

 Prof. Sohaaffhausen accounts for this difference between the 

 races by " the posterior dental portion of the jaw being always 

 " shortened" in those that are civilised,'" and this shortening maj , 

 I presume, be attributed to civilised men habitually feeding on 

 soft, cooked food, and thus using their jaws less. I am informed 

 by Mr. Brace that it is becoming quite a common practice in the 

 United States to remove some of the molar teeth of children, as 

 the jaw does not grow largo enough for the perfect development 

 of the normal number.*" 



With respect to the alimentary canal, I have met with an 

 account of only a single rudiment, namely the vermiform appeii d- 

 age of the caecum. The caecum is a branch or diverticulums 

 'tne mtestlue, yhtrTng in a cul-de-sac, and is extremely long in 

 many of the lower vegetable-feeding mammals. In the marsu pial 

 koala it is actually more than thrice as long as the whole body.^* 

 It is sometimes produced into a long gradually-tapering point, 

 and is sometimes constricted in parts. It appears as if, in con- 

 sequence of changed diet or habits, the cseoum had become much 



« Dr. Webb, ' Teeth in Man and from Florence, that he has lately 



the Anthropoid Apes,' as quoted by been studying the last molar teeth 



Dr. C. Carter Blake in ' Anthi-opo- in the different races of man, and 



logical Review,' July 1867, p. 299. has come to the same conclusion as 



" Owen, ' Anatomy of Verle- that given in my text, viz., that in 



brates,' vol iii. pp. 320, 321, and the higher or civilised races they 



325. are on the road towards atrophy oi 



*• ' On the Primitive Form of the elimination. 

 Skull,' Eng. translat. in ' Anthropo- *° Owen, ' Anatomy of Verte 



logical Review,' Oct. 1868, p. 426. brates,' vol. iii. pp. 416, 434, 441. 



*^ Pi-cif M'r.tegrzza writt:, to me 



