THEORY OF SEX-DIMORPHISM 87 



ment the r61e of hormones by recognising the 

 importance of metabolism-stimulation. 



Using the terminology of The Evolution of 

 Sex, Geoffrey Smith says of the adaptive 

 regulation of the metabolism in the parasitised 

 male crab that " this adaptive regulation 

 consists in the production of at least a par- 

 tially female condition of metabolism as op- 

 posed to a wholly male condition, the female 

 condition being preponderantly anabolic or 

 conservative, as opposed to the katabolic 

 male condition, and by this change from a 

 katabolic to a more anabolic condition the 

 animal can withstand better the drain on its 

 system increased by the parasite." 



SEX-CHARACTERS AND SPECIES-CHARAC- 

 TERS. The interesting thesis has been already 

 mentioned (Tandler, Kammerer, Tandler and 

 Grosz), that sex-characters have been derived 

 from ordinary species-characters, w^hich have 

 been brought into special correlation with the 

 reproductive organs and their internal secre- 

 tions. Tandler writes : " All secondary sex- 

 characters were indeed at first specific char- 

 acters . . . and not primarily associated with 

 the genital sphere." Thus the milk-gland has 

 doubtless arisen from a group of sebaceous 

 glands, common to both sexes. Later on, it 

 underwent transformation, and in the female, 

 came into the service of another function, and 

 under the influence of the gonads. There is 

 no puzzle in the fact that it is represented in 

 an undeveloped state in the male. 



Kammerer comes to the same conclusion : 

 " The sex-characters simply form a particular 

 group of species-characters : all sex-characters 



