THE ORIGIN OF MAN 119 



ability, the common possession of the females of all mammals. 

 It is almost pathetic that the one human distinction upon 

 which all authorities are agreed, the one around which so 

 many interesting theories have centred, and to which a 

 peculiar literature attaches, should be the very one which 

 must be cast aside as untenable. But one other remains, and 

 this is a detail to which far less attention has been devoted. 

 The human penis is perhaps the very simplest expression of a 

 male copulatory organ to be found anywhere in the mammalian 

 phylum ; it differs very remarkably in general form from that 

 typical of the monkeys and anthropoid apes ; and the fact 

 that no os penis, and no trace of cartilage, are formed in it 

 at any phase of its development severs it utterly from the 

 corresponding organ in all the Primates save Tarsius. 



We must content ourselves with this as the sum of our 

 brief outline of the story of the structural distinctions of 

 Homo, and it has ended on a note which merits especial atten- 

 tion. Tarsius, alone among the Primates, resembles Man in 

 having no cartilage or bone developed in the penis. Tarsius 

 resembles Man in the structure of the kidney. In Tarsius 

 only are the aortic vessels arranged in all examples as they 

 are in Homo. The tongue of Tarsius shows the basal type to 

 which that of Man may be referred. In most of those cranial 

 features in which Man differs from monkeys, Tarsius resembles 

 Man. Man resembles the monkeys in much. In more he 

 resembles the anthropoid apes ; but in other points (which 

 are not human specialisations) in which he differs from the 

 anthropoid apes he still finds a likeness in this curious little 

 creature. Tarsius we have assumed to be a very near likeness 

 of Anaptomorphus of the Eocene the first recognisable an- 

 cestor of the Anthropoidea. Man is undoubtedly linked to 

 this early form by many bonds, and the bonds become less 

 (except in purely superficial adaptive convergent likenesses) 

 as advance is made via the inverted order of anthropoids and 

 monkeys. In a very large number of features, Man, where he 

 differs from the anthropoids, resembles Tarsius, and where 

 the anthropoids differ from the monkeys they resemble Man. 

 This distinction holds true in practically all cases, except 



