862 



AQUATIC PHYCOMYCETES 



repeated mitotic divisions of the single nucleus of the zoospore during 

 its germination. In the basal cell ol Rhipidium, which is even more 

 developed than that of Sapromyces, Behrens (1931) noted that the many 

 nuclei formed migrate into the developing hyphal branches, which as a 

 result become nucleated. 



The nuclei appear to flow with the protoplasm into the rudiments of 

 the zoosporangia, for no division figures have been observed. Once the 

 sporangium attains its full size it is cut off from its attendant hypha by 

 a basal hyaline plug. The nuclei are at first irregularly arranged in the 



Fig. 67. Cytology of Apodachlya brachynema (Hildebrand) Pringsheim 



A. Immature terminal oogonium and hypogynous antheridium, showing 

 arrangement of nuclei. B. Simultaneous mitoses in oogonium and antheridium. 



C. Oogonium with nuclei in peripheral position prior to their degeneration. 



D. Oogonium and antheridium, showing gamete nuclei and a number of 

 degenerating peripheral nuclei. E. Primary zoospore with the two anterior 

 flagella each connected to a distinct basal granule, which in turn is connected 

 to nucleus by a delicate strand. F. Secondary swarmer, with the two laterally 

 placed flagella each attached to a distinct basal granule, which in turn is 

 attached to nucleus. G. Oogonium with thickened wall (oospore?), with the 

 two gamete nuclei closely associated but not yet fused. H. Oogonium bearing 

 nearly completely fused nuclei, from which a few astral rays emanate. 



(A-D, G-H, Kevorkian, 1935; E-F, Cotner, 1930b) 



