NEW INTERPRETATION OF CNIDARIA 289 



by way of postgamous divisions which are again heterocyclic ; 

 their result is usually a vegetative, complex, or polyploid 

 karyon (macronucleus), and a primitive, sexual, diploid 

 karyon (micronucleus). 



Scholars such as, Jennings, (1939) have tried to interpret 

 the Infusoria (Paramecium) as gonochoristic animals. Ac- 

 cording to such an interpretation, the two so-called pronuclei 

 (actually the gamete karyons) which frequently do not differ 

 externally from each other, are supposed to belong to the same 

 sex, they are supposed to be both androgametes or gynogame- 

 tes. If this were true, then only two individuals which belong 

 to the opposite sexes would be able to conjugate. Such a case, 

 though theoretically not impossible, is completely improbable. 

 In numerous hermaphroditic species of Eumetazoa with a 

 uniform hermaphroditic gonad (e.g. in the Roman snail 

 Helix pomatius, as well as in some Protozoa, e.g. in the 

 Heliozoa) we can observe that the sexual cells of the two sexes 

 can be developed by way of a heterocyclic division from an 

 "indifferent" primitive sex cell. This can lead in special cases, 

 e.g. in numerous Euciliata that have adopted a sessile way of 

 life, that— under the influence of a strongly developed sexual 

 dimorphism of praegamonts— the microgamont which becomes 

 free begins to function as a male, and the sessile macrogamont 

 as a female; yet in spite of this we can observe in both of them 

 a clearly hermaphroditic nature. 



J. P. Turner (1941, in Protozoa in Biol. Research : 617) expres- 

 sed his opinion that conjugation cannot be considered as a 

 propagation or a reproduction, but rather as a reorganization 

 only. I believe this interpretation to be w^rong, it agreeing only 

 with the external superficial appearances. It has already been 

 stressed that conjugation completely corresponds to a propa- 

 gation or reproduction, combined with the sexual act; the only 

 difference is that it is rather modified and somewhat concealed. 

 Not even the usual consequence of the fertilization which takes 

 place during conjugation is missing; it is manifest in Protozoa 

 with free and numerous agametes in the postgamous divisions 



