Timherlalift — Swa7-m-S pores of llydrodictyon. 515 



J 



twcon the spermatozoon and the swanrispore. The cilia of tlie 

 swarrnspore clearly bear tlie .same relation to tlie hasal body 

 as does the axial filament to the middle piece or more particu- 

 larly to that part of the middle piece derived from a centro- 

 some. But whether the basal body really corresponds to the 

 middle piece must be left unsettled until its origin is deter- 

 mined. 



Discussion of the question as to whether the basal body in 

 llydrodictyon corresponds to the blepharoplast of some Pter- 

 idophytes and G^minosperms, is for the present quite prema- 

 ture. That question is also quite distinct from the further one 

 as to the homology of the blepharoplast itself. 



The development of the swarm spores in such forms as 

 Cladophora and Ocdogonium needs to be carefully investi- 

 gated. Strasburger's (24) conclusion that the individual 

 nodule at the base of each cilium is merely a swelling of the 

 plasma membrane was based entirely, so far as his descrip- 

 tions and figures indicate, upon the study of the fully formed 

 spores. It is quite possible that early stages in the develop- 

 ment of the spores would show that the origin of both the 

 cilia and the nodules at their bases is quite different from 

 what Strasburger supposed it to be. 



University of Wisconsin, Xovember, 1901. 



