49 



the relationships which exist between these structures culture 

 experiments were begun. 



"Usinga micropipette a few zoospores were collected from a 

 germinating fusiform sporangium and sown in sterile charcoal 

 water in a petri dish containing a young culture of pure Achlya. 

 Within twenty-four hours several fusiform sporangia appeared 

 in the Achlya filaments. Each zoospore gave rise to a sporan- 

 gium without fusions to produce a Plasmodium. 



"From this culture single sporangia were isolated and mono- 

 sporangium cultures of the fungus were established. The pri- 

 mary infection of the pure Achyla culture resulted again in the 

 production of a few solitary fusiform sporangia. However in 

 the course of four or five days secondary infection took place 

 and large swellings were formed in the filaments which con- 

 tained many spherical to cylindrical zoosporangia varying in 

 size over a large range. Finally many of the sporangia became 

 spiny but germinated directly. Spherical, thick-walled, spiny 

 resting spores were observed in cultures five days old. 



"The various types of sporangia which Fischer described for 

 his species are simply modifications of one form which seem to 

 be dependent upon the amount of nourishment which the de- 

 veloping thallus can derive from the host. The "resting spores" 

 which he described are zoosporangia w^hich become spiny in ac- 

 cordance with the age and condition of the host. The true rest- 

 ing spore is spherical, thick-walled and spiny differing from that 

 of Olpidiopsis only in the absence of the adjacent cell." 



Mr. Hillegas spoke on the "Cytology of Endochytrium." 



"The chytridiaceous form Endochytrium is a member of the 

 Rhizidiaceae. The mature thallus consists of a typically flask- 

 shaped, operculate zoosporangium and a well developed 

 branched rhizoidal system. In addition to the evanescent spo- 

 rangia thick-walled resting spores are formed. 



"The sporangium develops as an enlargement of the germ 

 tube. The protoplasm is at first hyaline, vacuolated and with 

 large refractive globules. The refractive globules and vacuoles 

 disappear giving rise to a uniformly granular protoplasm. 

 These granules fuse to form the refractive globules of the zoo- 

 spores. A wall is formed between the rhizoid and the sporangium 

 at the granular stage. Nuclei are not found in the rhizoid and 

 evidence indicates that the cytoplasm is withdrawn from the 



