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WM. H. WESTON 
"gemmae" ; .but formed sexual organs rarely under normal culture 
conditions, and in haemoglobin solution only at the specific concen- 
tration of 0.025 percent. Another form, Saprolegnia monoica var. 
vexans, after reproducing only non-sexually during sixteen months 
of cultivation on various substrata which had induced sex organs in 
other forms, finally produced an abundance of oogonia and antheridia 
under the influence of a combination of ikf/200 levulose and M/200 
leucin. Moreover, in addition to these two species, Pieters mentioned 
a Saprolegnia (no. 66) forming numerous single spherical "gemmae," 
and yet, during eighteen months of cultivation, absolutely failing to 
respond by the formation of sex organs to the usually successful 
methods of culture. 
In the genus Achlya, also, there have been reported somewhat 
similar forms which show a lack of sex organs coupled with the for- 
mation of resistant structures. Under the name of Achlya oidiifera 
Horn (4) described a form which under long continued observation in 
pure culture, and with the most exact methods of cultivation, showed 
consistent non-sexual reproduction. None of the conditions by which 
Horn induced the formation of great numbers of oogonia in Achlya 
polyandra de B. were successful in the case of Achlya oidiifera. In- 
stead, there developed oidia-like hyphal segments which formed 
zoospores at once, or rested even as long as a month and were still 
capable of further growth. In his study of Achlya oidiifera, Horn 
observed oogonia only once within an ant egg on which he had grown 
the fungus; and although no antheridia were found on account of the 
advanced stage of 'development, the pits on the oogonium wall, and 
the eccentric zoospores, suggested Achlya polyandra de B. or some other 
member of the prolifera group. 
More recently Coker (i) made a careful study in pure culture of 
Achlya paradoxa, a species frequently collected by him in North 
Carolina, and unique in the aberrant behavior of its zoospores. The 
fungus when isolated from single zoospores produced zoosporangia 
and " chlamydospores " in abundance. Although the form was for a 
long time maintained in pure culture under a variety of conditions, 
sexual organs proved very rare. They were observed but a few times, 
and their formation could not be induced by a great variety of sub- 
strata including nutrient solutions of various kinds containing organic 
or inorganic salts. 
The peculiar Achlya described by the writer in the earlier part of 
