292 SEA-SIDE STUDIES. 



To this list may be added the A Igce, in which Pringsheim 

 has observed the same phenomenon.* 



Such were the facts known at the time Avhen I resumed 

 my investigation of Polype-parthenogenesis. The labours 

 of distinguished naturalists on the genesis of Polypes may be 

 summed up in the following schema : 



A. The Medusa parent ijroduces ova ; 



B. These ova are developed into infusoria ; 



C. These infusoria are develoj^ed into Polypes ; 



D. These Polypes 2:)roduce, hy budding, the Medusae, 

 which in turn 2)roduce ova. 



Thus D completes the cycle commenced at A. As varia- 

 tions from this route we have — 



a. The Medusa produces Medusas by budding ; 



/3. The Polype produces Polypes by budding ; 



7. The Polype produces Polypes hy ova directly, i. e. 

 "U'itliout going through the ]\Iedusoid generation. 



Attention is called to this second table, because the facts 

 therein resristered have been too often lost si2;ht of in the 

 discussion of the theory. When, for example, so much stress 

 is laid on the analogy between the development of a Polyjie 

 into a ^ledusa, with that of a bud into a flower, it is appa- 

 rently forgotten that, in spite of the resemblances, great 

 differences are discoverable. No flower produces similar 

 flowers by a process of budding, as the Medusa buds off" 

 young Medusa3 from its substance : a rose does not split 

 up into a dozen roses. 



* Annates des Sciences Jfatttrelles. 1856. 



