72 Transactions of the South African Philosophical Society. 



inner thick and pigmented ; the capitellum stands out conspicuously 

 from the floor of the ruptured spore cyst. 



The Spoees. 



These, as I have said, are ovoid or ellipsoidal bodies of light brown 

 colour, and semi-transparent, the pigmentation is evidently chiefly 

 in the cell wall ; many of them appear more pointed at one end than 

 at the other, and there is also a want of bilateral symmetry, in the 

 majority, one side being the more flattened ; their sizes equal the 

 diameter of a red blood corpuscle in length and one-half or one-third 

 as broad. I have calculated that there are often as many as 200 

 spores in a single spore cyst. When in the space covered by a square 

 surface of one-quarter of an inch of the fungus growing on nutrient 

 medium I have counted as many as 100 spore cysts the enormous 

 fecundity of the fungus may be imagined ; 20,000 spores being pro- 

 duced in this area, or 320,000 to the square inch. 



Development of the Spoees. 



The spores when they reach maturity, and are ejected from the 

 spore cyst, are ovoid or boat-shaped in contour. For examining the 

 development of the spores I used a fine film of gelatine pressed 

 between two cover glasses separated to the extent of the thickness of 

 a cover glass ; a rim of Canada Balsam round the edges of the cover 

 glasses made a closed cell which could be fixed to a glass slide. The 

 development of the spores shown in the gelatine could then be easily 

 watched from day to day under the microscope. Observation 

 showed that at ordinary temperature in twelve hours the ovoid spores 

 had become much larger and had lost the ovoid form and become 

 circular. In twenty-four hours further a still greater increase in size 

 had occurred and the spores had begun to sprout ; in twenty-four 

 hours further the sprouts had greatly increased in length and showed 

 the characteristic alternate branching and the segmentation of the 

 mycelium. Examined with a high power the spores at the end of 

 the first twenty-four hours were not distinguishable from the conidia 

 of the fungus ; the cell walls had become thin and the protoplasm 

 from being homogeneous had become granular and vacuolated. The 

 vegetative process was from this stage exactly as I have described it 

 in the case of the vegetative conidia ; sprouting, elongation of the 

 sprout, and branching of the mycelium thus formed taking place ; thus 

 the growth was as given above : first the formation of mycelium, 

 then the throwing off of conidia, finally the formation of spores by 

 sexual reproduction. The cycle from spore to spore occupied, at 

 room temperature, about five to six days. There may possibly have 



