104 THE SAPROLEGNIACEAE 



of protoplasm and comes only from the true antheridial cell either below 

 or on lateral stalks ; the other is thick-walled and knotted and very soon 

 without protoplasm and grows in from below only when no antheridial 

 cell is cut off. This is exactly like the tubes that enter so often the 

 oogonia in the Femx group in Saprolegnia and the ProUJera group in 

 Achlya. The last kind is certainly functionless; while the first-mentioned 

 are probably functional. 



The following 20 observations were made on cultures from No. 2 

 of September 10, 191 2: 



On ant in rain water. Sporangium seen to discharge at 10:55. Spores emerged rapidly, 

 and expanded into an open cluster. All the more distant ones fell away and dropped 

 at once to the bottom, at rest, where they lay in an open cluster, some at a distance 

 from others, some in contact. The other half remained attached to tip of sporangium 

 in an irregular, apparently solid, mass. There was no motion, except at very moment 

 of escape, when the separate ones on periphery were seen to rock a little. The spores 

 were watched, and they began to emerge from their cysts at 1:05, showing a rest of 

 2 hours and 10 minutes. 



On egg yolk in distilled water. Spores emerged rapidly, and behaved exactly as described 

 in preceding experiment, except that about ^4 of the spores fell at once to bottom, and 

 that there was a very obvious movement in all the spores that could be seen individ- 

 ually. This movement consisted in a rocking and slight change of place and readjust- 

 ment. This lasted only a few seconds. 



On egg yolk in .1 % CasCPOOa. Three sporangia were seen to discharge. Two dropped 

 all spores to bottom, and slight swimming movements were noticeable in outer ones. 

 One sporangium was put on glass slide and then discharged. The spores spread at 

 once in a loose colony, and most of them showed a decided rocking and change of place, 

 far more plain than in the other cases. They could readily be watched in the \ery 

 shallow water, and their movement was unmistakable. 



In nearly sterile pea broth. Grew beautifully through the broth and formed a dense mat 

 on the surface. In this mat were formed many normal oogonia. None were formed 

 below the mat. This culture was transferred from the test tube in which it was origin- 

 ally made to a petri dish and more pea broth added. Soon the whole mycelium was 

 plentifully dotted with oogonia that were quite healthy though bacteria had by this 

 time become abundant. The great majority of the oogonia were either with hypog- 

 ynous antheridia or none, but several were found with antheridia coming from a dis- 

 tance, as in figs. 6 and 11, pi. 30. 



On corn meal agar. Extensive growth. Many gemmae and very many oogonia. These 

 were larger than usual and less spiny. About half contained 3, 4 or 6 eggs, while in 

 other conditions, such as on ants and in pea broth, a great majority contained only one 

 or two eggs. No antheridia were present, and the spines were ver\' much reduced. 

 No inflated or abnormal oogonia. 



In pea broth. Good growth, but did not fill dish. Many normal sporangia, and very 

 many oogonia, these quite spiny and the vast majority with only one or two eggs 

 No antheridia seen. The only resting bodies seemed to be arrested oogonia. 



In maltose 5% peptone .01%. Vigorous growth, filling dish. Many inflated oogonia, 

 some without spines, but irregular in outline. No good eggs and no antheridial tubes. 

 No sporangia or gemmae. Protoplasm of the hyphae became segregated into dense 

 little bits at intervals. Most of the oogonia have good long spines. A part of this 



