94 THE SAPROLEGXIACEAE 



resists quite stubbornly all efforts to produce oogonia by artificial methods. Sub-cultures 

 from the above ha\e been made on grubs in pure water and few cultures produced any 

 oogonia at all." 



A number of experiments have been made to induce the formation 

 of oogonia. The results of some of these are as follows: 



On a bit of whole egg agar in distilled water. Growth vigorous and healthy. Sporangia abun- 

 dant, emptying normally and proliferating laterally' from below. No oogonia or gemmae. 



On a bit of whole egg agar in distilled water. Growth vigorous, reaching a diameter of 4 

 cm. Sporangia slow to form, but after full growth appearing rather plentifully. Gem- 

 mae of usual shape present, but not plentiful. No oogonia. 



On a bit of hard boiled egg yolk in distilled water. Growth vigorous, reaching a diameter of 

 4 cm. Sporangia abundant and formed earlier than in culture above. Gemmae 

 plentiful. Oogonia present, but scarce. Antheridia of diclinous origin. As this was 

 a culture from a single spore, the presence of antheridia proves that the plant is not 

 dioecious. 



On a bit of whole egg agar in spring water. Growth vigorous and strong. Many gemmae. 

 No sexual reproduction. 



On fiy in spring water. Growth vigorous. Many sporangia, all proliferating from side 

 below as in Achlya. No gemmae. 



On corn meal agar. Growth extensive, filling dish. Aerial branches nearly reaching cover, 

 but not dense. Only gemmae present. 



In 5 per cent maltose +0.1 per cent peptone solutions mixed half and half. Growth 

 vigorous and healthy. A few small sporangia were formed, but the spores were only 

 imperfectly discharged. Also a few of the characteristic knob-like gemmae. 



On corn meal agar in tightly stopped sterile bottle. Growth vigorous, extending across 

 bottle and making a mold-like aerial growth an inch high. On examination there 

 were found only single gemmae, most of which were quite empty, they having sprouted 

 by a slender thread about t,\i. in diameter. In fact all the growth was remarkably 

 slender (.^[i, in diameter), enlarging to normal size only just below the gemmae. 



On corn meal and egg yolk agar. Growth very strong, covering dish and developing abun- 

 dant aerial hyphae that reached the cover. No reproduction of any kind. 



The following six cultures were all made on termites in distilled 

 water with the salt added as indicated : 



In 0.1 per cent KXO3. Growth good. Normal sporangia, discharging and spores taking 

 second swim, as was the case in all except the last of these six cultures. Many good 

 gemmae of usual shape, the larger ones having a tendency to form the cross wall some 

 way up from the base. No sexual reproduction. 



In 0.1 per cent KH2PO4. Growth good. Many gemmae. No sexual reproduction. 



In 0.1 per cent Na2HP04. Growth good. A good many gemmae, but not so numerous as 

 in the preceding cultures. No se.xual reproduction. 



In o.l per cent CasCPOi)^. Growth good. Many gemmae of usual shape. No sexual re- 

 production. 



In 0.1 per cent CaCNO,).. Growth good. Many gemmae."" No sexual reproduction. 



In 0.1 per cent K5SO.. Growth slight. Culture infested with fungus. Sporangia formed 

 but not discharging. A few gemmae. No sexual reproduction. 



