.\pii.\N()MVCp:s 165 



DeBary's measurements for the eggs compared with ours are rather 

 large, his being 27-35^ in diameter. He remarks ('60, p. 173) that in 

 this species the spore liall at the sporangium mouth may be two 

 spores thick around the central cavity and that the spores at the moment 

 of emergence are held together very weakly and may be separated from 

 each other and from the sporangium mouth by a slight current of water. 



All the following cultures were made from No. 10 of January 30, 



1913: 



In equal parts maltose 5% + peptone .01%. Growth only about yi inch in diameter. 



No reproductive bodies. 

 On white of egg in distilled water. Good growth and a good many scattering oogonia with 



antheridia. 

 On ant in distilled water. Good growth. .An immense number of good oogonia with 



antheridia. .Also sporangia. 

 On mushroom grub in distilled water. Good growth. .Abundant oogonia. 

 On corn meal agar. Growth strong, covering dish. Oogonia quite scattering, but many 



in the dish, all with antheridia and good eggs and with tubercles of about usual size. 

 On corn meal egg yolk agar. Growth fine and strong. .An immense number of fine oogonia, 



all with antheridia and good eggs. 



Experiments to test best method of preserving live cultures: 

 Culture put in vial on corn meal agar on March 18, 1913. When tested on December I, 



1913, it was found to be dead. 

 Culture on corn meal agar put in vial of water which was closed with a plug of cotton and 



put in a dark place in May, 1913. When tested in December, 1913, it was found to 



be alive. .All eggs seemed to be dead. 

 Culture put in aquarium jar with algae in laboratory. When tested on September 18, 



1917, no growth appeared. 



4. Aphanomyces parasitica^n. sp. 



Plate 57 

 Hyphae parasitic on vegetative threads, young sporangia and young 

 oogonia of species of Achlya {A. flagellata, A. Orion, sterile Aclilya, No. 

 I of August 13, 1921), not attacking the gemmae or eggs. Vegetative 

 hyphae endophytic at first, traversing the Achlya threads from base to 

 tip, and growing out through the walls of the Achlya only after exhausting 

 the threads. Threads of parasite 3-5.5'^ thick, most about 4,j.; straight 

 and even at first, becoming somewhat swollen in places and distorted 

 with age. Sporangia usually formed outside the host and emptying 

 normally for the genus, the spores encysting at the sporangial tip. If 

 formed within the host, which is not rarely the case, the spores do not 

 emerge, but encyst within the sporangium. Spores 7.4-1 iti thick, di- 

 planetic. Oogonia usually borne within the Achlya thread, not rarely 

 without it, on short, lateral, inconspicuous branches, I4-22,a thick, not 

 including spines; wall warted to strongly spiny, spines rarely up to y^ 

 long. Eggs single, eccentric, filling the oogonium, 12.8-21.71j. thick. An- 

 theridial branches of diclinous origin, usually long; antheridia single, 

 irregularly oval, 11 x 14,1; applied to the base of the oogonium and often 



