1898.] Swan. — The Genus Lepiolegnia, 53 



always diclinous in origin. The oospheres mature rapidly in 

 the oogonium, which is at first densely filled and opaque ; by 

 the sixth day they appear mature, and are clearly outlined. 

 They number from five to twenty — -usually about ten — are 

 globular in shape, centrically placed, and measure about 

 20 IX in diameter ; the oogonium is always globular and 

 shows no pitting (fig. 6). The non-sexual zoospores are not 

 produced until the oospores are well developed, that is about 

 the end of the fifth da}^ ; their appearing after the sexual 

 fruit is remarkable, as in other genera of the family this 

 order is usually reversed. When once zoospore liberation 

 sets in, it soon becomes general, and does not cease till 

 the remaining filaments are all reduced to empty exhausted 

 zoosporangia. These filamentous sporangia are about 14 /i. 

 in diameter and filled with zoospores for their entire length j 

 there is no septum visible. The spores can be traced when 

 at rest into the nutrient substratum, and when moving they 

 can be still more clearly seen as they emerge from it. From 

 these and other observations, I am of opinion that the 

 zoosporangia are joined directly to the root-filaments, the 

 dividing cell-wall, or septum, being hidden within them. 

 The zoospores when mature are of short sausage-shape, 

 about 8 X 15, with a clear interval of space betw^een them. 



The rounded extremity of the zoosporangium persists, but 

 when the first zoospore escapes it carries with it the end of 

 the cavity- wall which encloses it, and this remains as a narrow 

 beak-like tube, about 8 /i. in diameter, through which the 

 zoospores are all liberated, one at a time, into the surrounding 

 liquid (fig. 3). 



Their passage is not too rapid for observation or counting, 

 as the narrow outlet offers some difficulty to their egress, 

 while obliging them to assume a more elongated shape. The 

 liberation may continue five minutes or more, as the last spores 

 come up in single succession between increasing intervals of 

 time, and it is at such moments that I have seen them emerging 

 from the mycelia. 



The beak-like extremity extending from the rounded end 

 of the zoosporangium (fig. 3) is characteristic of Leptolegiiia 

 bandoniensisy and it increases in length with each liberation 

 that takes place through it^ 



