562 DESCRIPTION OF FIGURES. 



Eig. 



14. — A green cell with red central substance, on the 

 point of assuming the motile form. 



15. — An encysted zoospore, with filaments of proto- 

 plasm, {P. setiger, Tlotow), a distant " envelop- 

 ing cell," two cilia, chlorophyll-vesicles, &c. 



16. — An encysted zoospore, with distant "enveloping 

 cell," green, gelatinous, primordial cell ; red, 

 granular, disseminated central substance, and a 

 colourless point, (P. papillatus, Elot.) 



17. — A very small, globular, encysted zoospore, {P. ro- 

 tundatiis, Plotow.) 



18. — An encysted zoospore, pointed at both ends, alto- 

 gether green, {P. rostellatus, Plot.) 



19.^ — Commencing division of the primordial cell into two. 



20. — A young pyriform primordial cell, around which 

 the " enveloping cell" is just beginning to show 

 itself distinct from the primordial cell. 



21. — An older cell, with colourless vacuoles. 



22. — Commencing division into two ; the wholly green, 

 primordial cell, closely surrounded by - the en- 

 veloping cell, shows a constriction in the middle. 



23. — Commencing division into two; each secondary 

 primordial cell has developed an enveloping cell 

 around itself, whilst still within the parent cell. 



24. — Commencing division into four. 



25. — An unusual and incomplete division into fiva; 

 four pointed, encysted zoospores, not completely 

 parted after the resorption of the common " en- 

 veloping cell," remaining connected by pro- 

 cesses arising from the point where the cilia are 

 placed ; a smaller portion has become organized 

 into a naked primordial cell, also connected with 

 the others. (Vide fig. 39.) 



26. — Only half of the primordial cell consists of the 

 green globular substance; the other half is a 

 colourless granular protoplasm, enclosing in the 

 centre a red substance resembling a nucleus. 



27. — An encysted zoospore in the commencement of 



