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TEXT-BOOK OF FUNGI 



into an enlargement of the conjugation tube, close to the 

 point of attachment ; the swelling gradually expands into 

 a spherical vesicle, and, being delimited by a membrane 

 after receiving the protoplasm, becomes a thick-walled 

 zygospore. The outer wall of the zygospore assumes a 

 pale yellow colour, and in some cases continues smooth, 

 in others is covered with short spikes, which begin to form 

 at the same time as the enlargement in the tube. The 

 whole process of forming a zygospore, from the attachment 

 of the conjugating tube and the maturation of the zygospore, 

 was completed, in the case observed by Nowakowski, in 

 about 6-7 hours. A few instances are known of the con- 

 jugation of 2-3 receptive with one supplying gamete, and of 

 the consequent formation of 2-3 zygospores. The zygo- 

 spore, as has already been said, is a resting-spore. It 

 germinates when its resting time is over, and produces a 

 zoosporangium like the non-conjugating plants.' 



Dangeard, who has recently studied the structure and 

 mode of sexual reproduction of Polyphagus euglenae^ has 

 added materially to the above observations, which were 

 conducted from a morphological standpoint only. This 

 author announces the important fact that the female 

 gamete contains only one nucleus, the male gamete also 

 contains one nucleus; these meet in the zygospore, but 

 remain indifferent to each other during the resting period, 

 and only coalesce at the moment of germination. The 

 same observer recorded for the first time the presence of 

 what he terms cysts, apparently the equivalent of azygo- 

 spores. These bodies are enclosed in a thick wall, and 

 enter on a resling-stage like zygospores, but are not the 

 outcome of conjugation. These cysts are said to be 

 ordinary cells, which, under certain unknown conditions, 



