[I TEETH: MEN AND APES 111 



Again, the Orang's skull is as devoid of excess- 

 ively developed supraciliary prominences as a 

 Man's, though some varieties exhibit great crests 

 elsewhere (Seep. 25) ; and in some of the Cebine 

 apes and in the Chrysothrix, the cranium is as 

 smooth and rounded as that of Man himself. 



What is true of these leading characteristics of 

 the skull, holds good, as may be imagined, of all 

 minor features ; so that for every constant differ- 

 ence between the Gorilla's skull and the Man's, a 

 similar constant difference of the same order (that 

 is to say, consisting in excess or defect of the same 

 quality) may be found between the Gorilla's skull 

 and that of some other ape. So that, for the skull, 

 no less than for the skeleton in general, the propo- 

 sition holds good, that the differences between Man 

 and the Gorilla are of smaller value than those 

 between the Gorilla and some other Apes. 



In connection with the skull, I may speak of the 

 teeth organs which have a peculiar classificatory 

 value, and whose resemblances and differences of 

 number, form, and succession, taken as a whole, are 

 usually regarded as more trustworthy indicators of 

 affinity than any others. 



Man is provided with two sets of teeth milk 

 teeth and permanent teeth. The former consist of 

 four incisors, or cutting teeth ; two canines, or eye- 

 teeth ; and four molars or grinders, in each jaw, 

 making twenty in all. The latter (Fig. 18) com- 



