Observations on Growth of Fungus Parasitic on Locusts. 71 



sexual process of reproduction ; that is to say, the protoplasm of two 

 separated individual cells unites and rapid segmentation of the proto- 

 plasm of the conjugating cell takes place, an oospore being formed. 

 The manner in which I have observed this process to take place 

 is as follows : — 



This reproductive function is established about forty-eight hours 

 after the mycelial growth has begun on the surface of the nutritive 

 medium. An aerial filament is observed branching, one of the short 

 branches being very granular and terminating in a large granular 

 conidium ; from the division of the stem another branch, the proto- 

 plasm of which is usually clear, and which may or may not be 

 terminated with an enlargement or globular swelling, runs up and 

 approaches the conidium, which it touches, and the protoplasm of 

 the two cells in contact intermingles. The process, however, may 

 very likely be more promiscuous, and I have seen appearances which 

 make me suspect that terminal conidia were fertilised from cells or 

 conidia of neighbouring filaments with which they came in contact. 



When fertilised the oospore and its sporophore grow with great 

 rapidity, the sporophore shooting up and outstripping the fertilising 

 branch. The oospore developes a thick cell wall, which assumes a 

 dark or brownish colour, and the protoplasm, which can be seen 

 rapidly segmenting, also takes on a golden yellowish colour. The 

 size of the oospore increases rapidly, and its cell wall becomes 

 thickened ; the sporophore also increases in thickness out of propor- 

 tion to the mycelium branch from which it springs ; with its growth 

 it forces itself up into the oospore, forming a secondary globular 

 enlargement or capitellum. 



Further Development of the Oospore. 



After fertilisation the oospore rapidly increases in size, the wall 

 thickens, and the enclosed protoplasm becomes densely and finely 

 granular and of a yellowish colour ; then segmentation makes its 

 appearance, the enclosed protoplasm apparently resolving itself by 

 condensation at numerous spots into numerous globular masses. 

 These became more defined in shape, and, losing their circular contour, 

 appeared ovoid or ellipsoidal. These ovoid light brown bodies are 

 the spores, and these individually now increase in size, causing the 

 rupture of the spore cyst. The spore cyst ruptures with violence, as 

 the cyst wall has by this time become dry and elastic ; this is shown 

 by the fact that the ruptured wall curls back after splitting. The 

 spores are thus thrown broadcast over the surrounding area ; from the 

 appearance of the ruptured cyst wall it is evident that it is at the time 

 of rupture composed of two layers, the outer fine and transparent, the 



