1064 AQUATIC PHYCOMYCETES 



zygote to contract away from the wall of its container, thus simulating 

 the egg of the Oomycetes. This suggested to her that here there exists an 

 intermediate condition of sexuality between that group and the Zygo- 

 mycetes. Couch (1939c), who studied the closely related genus Conidiobo- 

 his, in which a similar condition exists, points out that actually no egg is 

 differentiated. In both papers (1939c, 1949) however, he carefully avoids 

 the use of the term "zygospore" for the mature zygote. Knowledge 

 concerning nuclear conditions in the gametangia and zygote is still 

 primarily derived from the work of Dangeard (1903b). He stated that the 

 contributory cell at first has two nuclei, whereas the receptive cell has 

 six or eight. A single simultaneous mitotic division in each doubles these 

 numbers. After union of the two gametes, plasmogamy but not karyog- 

 amy occurs and the mature resting structure is multinucleate. Germi- 

 nation of the resting zygote is by a hypha. 



SYSTEMATIC ACCOUNT 



ENTOMOPHTHORA LES 



The order is usually considered as composed of a single family. 



ENTOMOPHTHORACEAE 



Mycelium inter- or intracellular, coenocytic at first but usually soon 

 becoming divided by septa into uni- or multinucleate segments which 

 may remain conjoined or separate into hyphal bodies which often 

 multiply, or form asexual reproductive or resting structures; nonsexual 

 reproduction by means of uni- or multinucleate conidia borne on 

 somewhat specialized conidiophores from which they are usually for- 

 cibly ejected; conidium giving rise to a mycelium, one or more secondary 

 conidia, or nonmotile endogenously formed spores; resting spores thick- 

 walled, either formed from a single cell ("azygospore") or, more com- 

 monly, sexually ("zygospore") after lateral or scalariform conjugation 

 between cells and then borne either within one of the conjugants, or in 

 an outgrowth from one, or at their point of union. 



Parasites of insects, desmids, and fern prothallia, and saprophytes in 

 vegetable debris and excrement of frogs and lizards. 



