SAI'KOI.IX.MA 37 



put on a slide in water in a moist ciiamber to test this again. Many spores 

 were formetl and coming to rest on the slide emerged again, leaving 

 a large number of cysts. 



The following notes were made on the development of the spores: 

 At one o'clock the outlines could be seen. These would appear and 

 then almost disappear in different jiarts of the sporangium. This happened 

 several times. At i:i6 tlie whole sporangium rapidly became homo- 

 geneous. After about 4 minutes the spore outlines began again to appear 

 and became pretty plain in five minutes. They continued in this con- 

 dition, the outlines getting gradually more distinct, for about 15 minutes 

 without change. All this time the spores (or protoplasm) were firmly 

 touching the wall, but now, about 4 minutes before emerging, there 

 could be seen a narrow space filled with sap between the spores and the 

 wall. The spores emerged at 1 142, popping out rapidly at first under 

 strong pressure and gradually reducing the pace. As soon as the 

 sporangium opened the column of spores shrank from the wall in 

 proportion as the escape permitted, the last ones forming a narrow 

 column right in the center. On emptying the sporangium became 

 slightly narrower and about 8;a, longer. Again: Small spores liberated 

 at 12:37 "^^'ce nearly all at rest by 12:50, all by 12:56 (in spring water at 

 room temperature of 18° C. a single sporangium was separated just before 

 discharge and the spores were liberated in a drop on a slide.) On emerging 

 the spores swim slowly and aimlessly, changing direction momently and 

 coming to rest in about 15 minutes. After se\eral hours they emerge and 

 swim very acti\ely (more than three times as fast as in first stage) and 

 with a definite aim, revolving slowly. They are slightly smaller than in the 

 first stage and have a slight groove down most of one side. 



By e.xamination of a large number of sporangia of all shapes and 

 sizes we find that in the majority of cases the large sporangia produce 

 the large spores and small sporangia (gemmae) produce small spores. 

 This is subject to numerous exceptions. As a rule the spores of a single 

 sporangium are all of one size, but in several cases we have seen the two 

 sizes in the same sporangium. Moreover, there are intermediate sizes, 

 but these are not nearly so numerous as the extremes. 



All the following cultures were made from a single spore culture 

 (size of spore not known) from No. 12 of January 30, 1913: 



On corn meal agar. Growth good. A good many gemmae 'n chains of two to four, a 

 condition not found in water cultures except very rarely. No sexua.1 reproduction. 



On white of egg in distilled water. Growth delicate. .■\ very few gemmae formed, soon 

 dying. .Apparently no sporangia. 



