OOMYCETES. 



101 



A fertilisation, a passage of the contents of the antheridium to the egg-cell, 

 has as yet only been observed in Pythium; in Phytophthora only one small 

 mass of protoplasm passes through the fertilising tube to the egg-cell; in Pero- 



FIG. 85. Empusn muscce (Fly-mould). I. A fly killed by the fungus, surrounded by a white 

 layer of conidia. II. The conidiophores (t) projecting from the body of the fly. Some of 

 the conidia, a few of which have developed secondary conidia, are attached to the hairs 

 (mag. 80 times). III. A perfect hypha. IV. A hypha in the act of ejecting a conidinm 

 (c), enveloped in a sticky slime (g). V. A conidium which has developed a secondary 

 conidium(sc). VI. A branched hypha produced by cultivation. VII. A secondary con- 

 idium which has produced a small mycelium (m). VIII. A conidinm germinating on the 

 fly's body. IX. Mycelium. X. Conidia germinating like yeast in the fatty tissue of the 

 fly. (III.-VII. and IX. magnifled 300 times ; vm. and X. magnified 500 times.) 



