BLASTOCLADIALES 637 



zoids or cell walls; reproducing by thick-walled, smooth or variously 

 sculptured, resistant sporangia which develop in the insect's hemocoele: 

 sporangia at first covered by a thin membrane formed from the old 

 plasma membrane, the wall proper consisting of two layers, the outer 

 thick, smooth or usually sculptured, and brownish in color, the inner 

 smooth and hyaline; in germinating, the outer membrane cracking 

 along a preformed groove much as in Allomyces, the inner wall and 

 the contents swelling and protruding through this slit; spores discharg- 

 ing later by the gelatinization and disintegration of the exposed surface 

 of the inner wall; zoospores posteriorly uniflagellate, with a nuclear 

 cap as in Allomyces; sporangial walls without cellulose. l 



Germination of the resting spores in Coelomomyces was first observed 

 by de Meillbn and Muspratt (1943). It was these workers that noted, 

 as had earlier been predicted by Keilin (1921), that the spore wall cracks 

 along a preformed line of dehiscence and that the contents (surrounded 

 by a membrane) over a day or more gradually extrude to the outside. 

 The most complete description of this process, as it occurs in C. lativit- 

 tatus, is furnished by Couch and Dodge (1947)(Fig. 44 L-M, p. 651). 

 They state: 



None of the material was dried and six days after it had been collected some 



of the sporangia had started germinating [A] few sporangia were seen 



to have a slight bulge on one side., and in others the swelling had gone far 

 enough to split the outer wall along the preformed line, exposing the inner 

 sporangial membrane, By this time the lipoid granules, which had been more 

 or less evenly dispersed throughout the cytoplasm, had aggregated in spherical 

 groups, each group destined to be the center of a spore origin, a stage char- 

 acteristic of other members of the Blastocladiales. About six to twelve hours 

 after the opening appeared in the outer wall the contents of the sporangium, 

 surrounded by the thin inner membrane, had pushed out through the slit to 

 form a dome-shaped extension. At this stage the spherical aggregates of lipoid 

 granules were very distinct 



The swelling of the internal contents of the sporangium continues until it 

 reaches its maximum, when the slit in the outer wall extends from one-half to 

 two-thirds the length of the sporangium and is broadly elliptical in outline. 

 The protoplasm, surrounded by the inner wall layer, protrudes through this 

 opening as a slightly flattened hemispheric mass in side view, but is really 

 about twice as long as wide. At this stage the spore outlines are distinct and 

 are polygonal from pressure the nuclear cap and nucleus, with the lipoid 



1 Revised for this treatise by J. N. Couch. 



