PROTOACHLYA 93 



coming to rest at once in a group. This behavior is only another proof of the fact lliat 

 sixircs are expclletl by sporangial turgor in this family and not by their own power. 



The existence of cilia thus indicated by the behavior of tlie spores 

 was doinonstratod by treatment with potassium iodide sokition at the 

 moment of emergence. A sporangium so treated is shown in plate 26, 

 fig. 3. All the spores can be distinctly seen to have cilia. From these 

 observations it will be seen that the behavior of the spores has no normal 

 parallel in the genus Achlya. 



Oogonia without stalks and with their bases formed from a section of 

 a hypha are not at all rare. Slender upgrowths into the oogonium 

 from the partition below are occasionally seen. Such growths often 

 appear in other species of Saprolegnia and Achlya, but, while they give 

 the efTect of antheridial tubes, they are apparently quite functionless 

 except perhaps in the cases where a hypogynous antheridium is cut ofif {A . 

 hypogyua and 5. hypogyna). The antheridia themselves are peculiar. They 

 are sudden enlargements of the tips of the antheridial branches and 

 are short, thick and tuber-like. They often proliferate, and usually 

 by growth from near the base of the antheridial cells themselves. These 

 outgrowths are then cut off as separate antheridia. When first formed 

 the antheridia are well filled with protoplasm and contrast strongly 

 with the almost colorless branches that bear them. Later the antheridia 

 appear almost empty as if they had discharged their contents into the 

 eggs. This, however, was not actually observed. Gemmae, unlike the 

 oogonia, are not rare, Init appear plentifully, though not densely, in al- 

 most all cultures. The majority terminate short branches and approxi- 

 mate the oogonia in size, shape and position (plate 26, fig. 6) ; others are 

 arranged in chains (fig. 6) which are usually curved or contorted. Elon- 

 gated and irregular forms are also produced from somewhat swollen and 

 knotted segments of the hyphae. Under ordinary cultural conditions, 

 such as on flies, termite ants, gnats, mushroom grubs, etc., in water, there 

 is usually no sexual reproduction. Out of a hundred cultures perhaps 

 one would show a few oogonia, and their appearance seems to be entirely 

 whimsical at times. For example, in a series of cultures made from 

 the same original, one of the cultures on a mushroom grub produced a 

 large number of oogonia, while others on the same as well as other media 

 produced none. On the other hand, the oogonia appear rather fre- 

 quently in cultures first appearing in the water brought in with the collection. 

 This fact is illustrated in the following note by Mr. J. N. Couch. 



"On July 25, 1918, I brought in ten glasses of water containing trash, leaves, sticks, 

 etc. The material was put into crystallizing dishes and in order to co\er the bottom well 

 more water was added from the spigot, and four or five grubs were dropped into each dish. 

 A few days later it was found that 7 out of the 10 collections had a fine growth of A. para- 

 doxa with abundant oogonia and a fine lot of typical sporangia. .As a rule A. paradoxa 



