115 



Extract from a Monograph, " Zur Kenntniss der Phycomy- 



CETEN." 



By Dr. W. ZorF, in the " Nova Acta Acad. Caesar. Leopold. 

 Carolin. Germ. Nat. Cur." Halle, Bd. XLVII., No. 4. 



Translated with the sanction of the Academy by George C. Karop, 



M.B.C.S., F.R.M.S. 



{Bead April 22nd, 1887.) 



Ectrogella Bacillariacearum,* Zopf. An Endophyte in- 

 festing the Diatom acea3. 



The author begins by stating that most observers of the Diato- 

 macese are aware that this family of the Alga? has enemies among 

 the Fungi and Mycetozoa. They belong partly to the group of 

 Monadines, partly to the ChytridiaceEe and Ancylisterc. 



He quotes Cienkowski's investigations on Vampyrella, vorax, 

 which low Myxomycete preys upon Diatoms of all species. Also 

 Braun and Nowakowski, the former of whom discovered the para- 

 sitism of Chytridium Lagenula on Melosireae, and the latter found 

 a form of the same parasitic on Epithgmia Zebra. In these how- 

 ever, the sporangia are developed externally to the host. 



Purely endophytic Diatom parasites were subsequently observed 

 by Focke, and again by Pfitzer. 



Having thus shown that a small series of Diatom parasites is 

 already known, the complete life histories of which however are 

 still wanting, the present author proceeds to a description of a new 

 and fatal enemy of the Diatomaceaa, which also possesses some 

 special morphological features. 



He says : I found the Ectrogella Bacillariacearum in a large- 

 celled Synedra, growing on the rootlets of Lemna minor, in 

 stagnant water. About the middle of November it occurred in 

 such numbers that 75 per cent, of the host-plants from this par- 

 ticular locality, near Berlin, were attacked by the parasite. In 



* From tKTpioyeiv = to eat up or devour. 

 Jouen. Q. M. C, Seeies II, No. 19. 10 



