112 Heredity. 



power of deycloping perfect functional mammae, and 

 that this power is arrested in the male, than to assume 

 that each male animal includes in itself a complete 

 female duplicate. 



An illustration may make the subject more clear. Cer- 

 tain embryo bees, when exposed to certain conditions, 

 develop into sterile workers, butjrvhen exposed to another 

 set of conditions they become fertile females. The dif- 

 ferences between the workers and the queens are not con- 

 fined to the reproductive organs, but extend to the shape 

 and size of the body, the general organization, and to 

 the instincts of the animals. These differences are not 

 due to the direct action of the conditions to which the 

 young are exposed, but are truly hereditary, as we see 

 from the fact that the workers of different species are as 

 distinct and as characteristic of their species as the male 

 or the fertile females. 



Now which is simplest, to assume that each female 

 embryo has a complete worker organization and a com- 

 plete queen organization, or to hold that it has the 

 power to develop all the characteristics common to both, 

 and also the distinctive characteristics of each; that one 

 set of conditions suppresses the distinctive characteris- 

 tics of a perfect queen, while another set of conditions 

 arrests those of a perfect worker ? 



The argument in favor of the multij^le personality of 

 individuals which is furnished by polymorphic commu- 

 nities is at least as strong as that furnished by the latent 

 transmission of secondary sexual characteristics. 



In the case of the polymorphic hydroids an egg-em- 

 bryo may give rise, by budding, to certain descendants 

 with fully developed digestive organs, but with no or- 

 gans of locomotion or reproductive organs, to other de- 

 scendants with organs of locomotion, but without diges- 



