ACHLVA 125 



that the spores are expelled by internal prrssurc. In some cultures the 

 spores will run larger in a good man\' of the sporangia without apparent 

 cause, for example, in No. 2 of December 12, 1913, they were at times 

 14.8-16.61x in diameter. 



Dictiosporangia have been seen a number of times, e.g., in No. 6 

 of January 7, 1914. In some cases oogonia are attached immediately 

 below the dictiosporangia (pi. 42, fig. 10). 



Oogonial reproduction is rarely either frequent or abundant in this 

 species, and in some collections this tendency towards sterility is carried 

 to an extreme (see under experiments below). 



In a culture on a mushroom grub in water from the Arboretum spring 

 a sporangium was made to discharge under a cover glass. The spore mass 

 broke up in part and a good many of the outer spores were carried to a 

 little distance and scattered, and their slight individual rocking motion 

 could much more easily be seen. Iodine when added clearly demon- 

 strated the cilia. 



At one time spores were seen to emerge from their cj'sts at room 

 temperature (about 72° F.) in about 5 hours after discharge, the emergence 

 occupying about 2 minutes. Most of the cysts were about I3.5;i. in diam- 

 eter, often with larger ones in the same sporangium, the latter mostly 

 about 22.5;x in diameter, and apparently the bulk of four ordinary spores. 

 These latter on emerging have several sets of cilia. After emerging 

 the spores scarcely rock for several minutes, then slowly rock, and finally 

 after more active rocking get away rather sluggishly after about 5-8 

 minutes. Most are about 12 X 14.5^ in last stage. 



The ele\-en following cultures were made from No. 4 of Novem- 

 ber 25, 1912: 



In agaricus l)roth. .Made a good start, but soon destroyed by an immense growth of 

 bacteria. 



In egg yolk broth. .A delicate growth, the hyphae soon losing their contents except for the 

 cut off tips, which look like small resting sporangia. Hyphae encrusted with amor- 

 phous granules. Bacteria not noticeable. 



In equal parts maltose 5% and peptone .01%. Grew rather slowly to about ^^ inch in 

 diameter, then became unhealthy and died. No reproductive bodies. 



On fly in jar of distilled water. Th • water was about one inch deep and the fly sank to the 

 bottom. Growth was very stout and bold — one inch in diameter. The hyphae 

 branched very little and all ended in sporangia, very few of which discharged their 

 spores completely. The majority did not open at all. Many of the spores sprouted 

 in position, and grew to some length. Xo other reproductive bodies. 



On corn meal agar. Grew well, covering agar, but no reproductive bodies were formed. 

 Hyphae gradually became colorless, and formed cross walls at places, segregating seg- 

 ments of denser material, .^fter about one month a test was made and the culture 

 found to be dead, even the denser sections. 



