ORDER ZOOPAGALES 179 



host from a conidiiim that adhered to the external surface of its victim 

 by means of a sticky substance. More rarely infection results from inges- 

 tion of the conidia. From this coil, after the death of the host, one or 

 more slender aerial unbranched or slightly branched hyphae which are 

 at first nonseptate emerge to the exterior. The terminal portion becomes 

 septate and from a few of the cells thus formed arise laterally sessile, 

 spindle-shaped conidia. Other short slender hyphae arising from the 

 haustorial coil grow parallel for a short distance and unite at the apex. 

 Just beyond the point of union a spherical thin-walled enlargement (called 

 by Drechsler, 1935a, the zygosporangium) is formed, equally upon the 

 apices of the two uniting hyphae or on an extension from near the apex 

 of one of them. Within this zygosporangium is produced an angularly 

 lobed, thick-walled zygospore. The zygosporangial wall may remain in- 

 tact and does not break up into small pieces and disappear as does the 

 corresponding structure in Mucorales. (Fig. 64.) 



In Cochlonema the thick spiral haustorial body much resembles that 

 of Endocochlus but the spindle-shaped conidia are in chains on the aerial 

 conidiophores. They are apparently ingested by the host and thus infect 

 it. Sexual reproduction is much as in that genus but in some cases the 

 zygosporangial wall is lobed or warty to correspond to the lobes or warts 

 of the zygospore. In Bdellospora the spindle-shaped conidia are also pro- 

 duced in chains. Instead of being ingested by the amoeba and forming a 

 coiled haustorium in its interior the conidium adheres to the outer surface 

 of the host cell and sends in a slender infection tube which divides di- 

 chotomously into several short lobes. The external conidium enlarges 

 until many times its original size and from it arise the aerial conidiophores 

 and also the slender branches (from separate individuals) that coil 

 around one another many times and then conjugate at the tips to form 

 a zygospore as in the foregoing genera. In Zoopage the mycelium is ex- 

 ternal, somewhat branched and nonseptate. When an amoeba comes in 

 contact with such a hypha it adheres to it and a short-lobed haustorium 

 penetrates the host cell. The external mycelium produces short aerial 

 chains of elongated spindle-formed conidia. Sexual reproduction is much 

 as in the preceding genera. Acaulopage and Shjlopage are similar but their 

 conidia are single, not in chains, practically sessile in the former and on 

 short conidiophores in the latter. The latter genus may attack Amoebae 

 and Nematodes. Cystopage produces no distinct conidia but intercalary 

 or lateral chlamydospores in the intramatrical mycelium as well as in 

 the extramatrical mycelium. It attacks Nematodes and Rhizopoda. 



Drechsler (1935) points out the similarity of the mycelium and catenu- 

 late conidia of some species of Actinomyces to those of some of the more 

 delicate forms in the Zoopagaceae and suggests that there may be some 



