Various Opinions on Heredity. 113 



tive organs or reproductive organs, and to still others 

 with reproductive organs, but with no organs of diges- 

 tion or locomotion. All these forms are hereditary and 

 are characteristic of the species, so there is no escape 

 from the conclusion that they all are present in some 

 form in the egg-embryo, and it is certainly natural to 

 suspect that the entire organization of each one of them 

 is latent in this embryo, but the explanation which I 

 have proposed to account for the transmission of second- 

 ary sexual characteristics, applies to such cases as this 

 just as well. 



The hypothesis that the egg-embryo inherits and trans- 

 mits to each of its descendants, those produced asexu- 

 ally as well as those produced sexually, all the characteris- 

 tics of the species, and that it also inherits and transmits 

 to each of them a tendency to suppress certain of these 

 characteristics under certain conditions, seems to furnish 

 a simple and satisfactory explanation of all the facts. 



According to this view the feeding zooids of a poly- 

 morphic Siphonophore are individuals which have inher- 

 ited in full all the characteristics of the race, but which 

 do not attain to perfect development in all respects. 

 The swimming zooids are similar individuals, with other 

 characteristics suppressed, and so on. 



This explanation seems much more satisfactory than 

 the supposition that the egg-embryo contains one com- 

 plete personality for feeding zooids, one for locomotor 

 zooids and one for reproductive zooids, and I hope that 

 this case will make clearer the lack of necessity for as- 

 assuming the dual personality of each male or female 

 animal, so long as we have a much simpler explanation 

 in the hypothesis that each embryo has the power to de- 

 velop all the characteristics of the species, together with 

 a tendency to suppress certain ones in each sex. 



