42 SEX 



all through the summer, without there being 

 any males in existence at the time; the eggs 

 in a bee-hive that are not fertilised develop 

 into drones ; in some of the wheel-animalcules 

 or Rotifers the males have never been found ; 

 the same is true of some of the gall-flies ; and 

 there are numerous parthenogenetic plants. 

 The question is, therefore, pertinent Why 

 is fertilisation the rule, seeing that many 

 creatures get on very well without it. The 

 probable answer must be that fertilisation is 

 of profound racial significance in affording an 

 opportunity for new departures and in tending 

 to secure a holding fast of that which is good. 



MALES AND FEMALES. The next step in 

 the evolution of sex above the clear differ- 

 entiation of egg-cell and fertilising element is 

 that of two distinct types of individual the 

 sperm-producer and the ovum-producer, the 

 male and the female. In Volvox we may 

 find the same colony producing numerous 

 ova and numerous sperms, and other colonies 

 producing only ova or only sperms. The 

 hermaphrodite or bisexual organisms that 

 occur at many levels in the animal kingdom 

 and are so common among Plants, represent 

 in part a pristine condition, and in part a 

 secondary incorporation of one sex by the 

 other in most cases, it may be, an acquisition 

 of femaleness by males. 



The fundamental problem is to account for 

 the evolution of two kinds of individuals 

 within the species the sperm-producers or 

 males and the egg-producers or females ; and 

 our view (developed many years ago in The 

 Evolution of Sex (1889), and briefly applied in 



