Classification. 75 



other cases only one arcliicarp is produced, yet the 

 separate gametes develop into bodies resembling 

 zygospores in structure and germination, proving 

 that conjugation or the blending of protoplasm from 

 two originally distinct cells is not indispensable for 

 the formation of bodies morphologically and func- 

 tionally indistinguishable from normally produced 

 zygospores. Such bodies are called azygospores. 

 Zygospores are usually restmg-sjpores, that is, they 

 possess the power of remaining in a dormant condition 

 for some months before germination takes place. 

 When both gonidia and zygospores are produced by 

 a species^ the general rule is that the gonidia appear 

 first and germinate at once, thereby adding greatly 

 to the number of individuals. This mode of increase 

 continues throughout the summer ; but such gonidia 

 are not resting spores, and do not survive through the 

 winter to produce new individuals the following 

 spring, but towards the autumn the gonidial phase is 

 arrested, and the formation of zygospores commences. 

 These remain passive during the winter as resting- 

 spores, and on germinating tbe following spring*, 

 produce bodies which find their way on to the special 

 host, and produce in turn the gonidial phase. When 

 zygospores are not produced, permanent mycelium 

 often enables the fungus to survive the winter 

 period. The most perfect sexual organs met with 

 in the division characterized by tbe formation of 

 oospores are developed as follows. The oogonia 

 originate as spherical swellings at the tips or intercalary 

 portions of the aseptate hyphge. After reaching con- 

 siderable size and becoming filled with dense protoplasm 



