CHYTRIDIALES 99 



lus is really absent or is merely more reduced at metaphase in C. 

 caroliniamtm than in C. laterale. No individual separate chromosomes 

 were recognized at the equatorial-plate stage in C. laterale, but in C. 

 caroliniamtm they were seen as irregular lumps in the equatorial-ring 

 and anaphase groups. 



J. Roberts (1948) studied the cytology of two species of the polycentric 

 operculate genus Nowakowskiella, N. ramosa (p. 586) and IN. profusa 

 (p. 585). In N. ramosa, the stained zoospore bears a prominent nuclear 

 cap over the nucleus. A blepharoplast and a rhizoplast are associated 

 with the flagellum. When the zoospore comes to rest the nuclear cap 

 presumably dissociates to form the deposit of large granules around 

 the nuclear membrane which, in some instances, radiates out to the 

 periphery of the spore body. A clear space adjacent to the nucleus no 

 doubt represents the position of the prominent oil globule in the living 

 spore. The nucleus proper contains a central nucleolus and a fine 

 reticulum. At germination of the zoospore a primary swelling or spindle 

 organ develops after the first dichotomy of the rhizoids. The nucleus 

 may remain in the spore case until the primary swelling appears or 

 it may pass into the unswollen tube which then enlarges around it. 

 If it stays within the spore cyst, the nucleus may divide there and the 

 daughter nuclei pass out individually into the primary swelling. Sub- 

 sequent growth produces further branches and nucleated swellings but 

 no cross walls. 



Numerous fiexuous, isodiametric or irregular filaments, usually ex- 

 tramatrical, arise from the sides or ends of the vegetative swellings or 

 develop between them. The filaments branch richly and elongate; fusi- 

 form swellings of even contour are usual in their proximal third. As 

 many as six nuclei are common in these enlargements, but they are 

 for the most part absent in the narrow lateral branches. Irregularly 

 swollen filaments or those lacking swellings contain nuclei scattered 

 throughout their length. 



The fiexuous extramatrical filaments bear the terminal or intercalary 

 sporangia. In their early stages the sporangia appear as somewhat elon- 

 gate fusiform swellings filled with granular cytoplasm and having a 

 single nucleus about 2 [j. in diameter. The tapering portion of the en- 

 largement which will become the subsporangial swelling has one or 



