88 SEX 



are at the same time species-characters." In 

 this connection he refers to Mobius's thesis 

 that there is a sort of somatic sex, a sex- 

 differentiation of all the organs and tissues, 

 whether they show a visible difference or not, 

 so that one may, he notes, invert the previous 

 sentence and say that all species-characters 

 are also sex-characters. But, in any case, 

 there are certainly no special sex-characters, 

 which stand apart from other species-charac- 

 ters, as things per se and autonomous. 



In their recent work Tandler and Grosz are 

 very emphatic in their conclusion that all sex 

 characters have been derived from specific 

 characters or " systematic " characters, which 

 in the course of time have been brought 

 (by the usual method of variation and selec- 

 tion) into the service of reproduction. This oc- 

 curred at different periods, as is suggested by 

 their different degrees of variability to-day. 

 And in the course of their evolution they have 

 come into correlation with the gonadial glands 

 of internal secretion which supply in a remark- 

 able way their indispensable liberating stimuli. 

 " The secondary sex-characters are, to begin 

 with, systematic characters and they ulti- 

 mately owe their development and differen- 

 tiation to the harmonious co-operating of the 

 glands of internal secretion." 



The thesis that : " All secondary sex- 

 characters were at first specific characters," 

 appears to us to be an exaggeration of a sound 

 idea. There are, it seems to us, numerous 

 peculiarities of one sex or the other which 

 cannot be readily derived from specific char- 

 acters supposed to be common to both sexes. 



