192 G. C. KAKOP ON CERTAIN IMMATURE FORMS OF DIATOMACE.E. 



diatoms produced from a sporangium or gonidia following the sexual 

 congress between two mature forms. 



Of course this method has long been surmised, but to my know- 

 ledge never witnessed ; so I merely wish to point out to those micro- 

 scopists who have sufficient means of research and leisure, a favour- 

 able opportunity of distinguishing themselves. 



