APODACHLYA 175 



niuiii. An oogonium grows from its first visible size to its mature size 

 in about eigiit hours. At the time when the oogonium reaches its mature 

 size the contents of all the stalk cells, except the one next the oogonium, 

 become less dense, while the oogonium and its adjoining cell are very 

 dense and homogeneously mottled. After a short rest the contents of 

 the dense cell pass over into the oogonium. This apparent fertilization 

 requires from three and one-half to five hours. Then after another 

 short rest organization of the contents begins. When the oogonium 

 finally falls away this subspherical cell adjoining goes with it, the chain 

 breaking below it. There is also a very significant change going on in 

 the oogonium during the reduction of the protoplasm in the adjacent 

 cell. A light spot appears in the proximal end in the hitherto homogene- 

 ous egg and this persists until nearly all the protoplasm has disappeared 

 from the cell below. It then disappears as the maturation changes set in. 

 While Zopf refers to the possibility of the cells he found attached to 

 the gemmae being antheridia, he concludes that they are more prob- 

 ably resting zoospores or invading organisms of other kinds. They 

 may well be antheridia. 



Our plant does fairly well in culture on termites in boiled well 

 water, and will grow well but slowly on corn meal agar. The sporangia 

 are very whimsical about opening at room temperature (about 60-70° F.), 

 but rarely fail to discharge their spores if kept in an ice box. 



On corn meal agar many of the segments become dumb-bell shaped. 

 One segment measured 23.4;^ thick at proximal end, I4;i. in middle, 2i;ji 

 at distal end, and was I05;j. long. The internodes of young threads are 

 open, as is evidenced by the fact that protoplasmic streams can be seen 

 passing from one segment to another, while those of old threads are 

 closed by a cellulin plug. Usually there are two or three globules of 

 cellulin in each segment. The globules are moved about by the action 

 of protoplasm, either pushed along in large segments or rotated in small 

 ones. Old segments are usually very dense with protoplasm, which 

 moves almost imperceptibly. Occasionally a sparsely filled segment 

 will be found between two densely filled ones; in it the protoplasm will 

 be in active motion, limited to its own walls by the cellulin plugs at the 

 internodes. It is on densely filled segments that oogonial branches 

 are borne. 



The spores on emerging are forced out under pressure, as usual in 

 the water molds, but the pressure becomes so weak before all are out 

 that several may sw-im around in the sporangium a few minutes before 

 getting out, and the last one or two, rarely more, are often retained 

 inside and encyst there after a few minutes' swim. Inside the sporan- 

 gium the spores are subspherical before emerging, Init in passing out 



