COURTSHIP AND SEX 219 



part of the inheritance of the females as well ; but they could 

 not find expression, so to speak, in the female constitution. 

 According to Tandler, however, they were originally 

 possessed by both sexes, like the horns of cattle, and have 

 in the course of time become sex-linked characters, normally 

 developed in the males only, except in the old-fashioned 

 reindeer where they occur on both sexes. 



Kammerer comes to the same conclusion : " The sex- 

 characters simply form a particular group of species- 

 characters : all sex-characters are at the same time species- 

 characters." Nevertheless, he distinctly favours 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 says, 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- 

 characters, as things per se and autonomous. 



In their recent work, " Die biologischen Grundlagen der 

 sekundaren Geschlechtscharaktere," i9i3,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 selection) into the 

 service of reproduction. This occurred at different periods, 

 as is suggested by their different degrees of variability to-day. 

 And pari passu with their evolution they have come into 

 correlation with the gonadial glands of internal secretion 

 which supply their indispensable liberating stimuli. " The 

 secondary sex- characters are to begin with systematic 

 characters and they ultimately owe their development and 

 differentiation to the harmonious co-operation of the glands 

 of internal secretion." 



In some birds there is a spur or weapon developed in 

 the carpal, carpo-metacarpal, or even digital region in both 

 sexes, as in Parra and Hoplopterus, the ducks Merganetta 

 and Plectropterus, and the screamers Palamedea and Chauna. 

 The spur is a specific character, and is used in fighting. If 



