^34 • 'T^^^ Irish Naturalist. [February, 



In L. caudata the rounded end disappears, being drawn out 

 to a narrower extremity at the moment of spore-liberation. 



The spores, when liberated, seem for a few seconds almost 

 devoid of movement. The}' at once twist over toward a horse- 

 shoe shape, and swing about languidly as though carried by a 

 current. The horse-shoe shape rapidly doubles up until the 

 two ends touch, after w^hich the whole fuses to an ovoid form, 

 and the zoospore moves off freel}- with increasing movement ; 

 this metamorphosis lasts about half-a-minute. 



When the zoospores are retarded in their escape from the 

 zoosporangium by an obstruction, the}' ma}' encyst to globular 

 shape within it, but this only occurs in an exhausted cultiva- 

 tion ; for they are, when in favourable growth, follow^ed by an 

 upward stream of fresh protoplasm into the empty sporangium, 

 and this may press them together so closely as to render their 

 definition difficult. 



At such time if the outlet be obstructed^by, say, a twist in 

 the sporangium— the spores make their escape at the side, 

 leaving a short beak or papilla which marks their place of 

 exit. 



It is not unusual in old cultures to see zoospores of var}'ing 

 shape in the same oogonium (fig. 4), their delicate uncovered 

 condition before encystment causing their form to be controlled 

 mainly by the space surrounding them; on liberation, however, 

 the narrow beak-outlet of the sporangium obliges them all to 

 assume the same elongated form. 



Chlamydospores are developed in unusual numbers at the 

 same time as the zoospores. They differ from the usual 

 description, as, though some few are placed terminally, they 

 are for the most part developed as large globular oogonium- 

 like vessels on stout lateral branches. 



They germinate readily by throwing out unusually large 

 hyphse, inside which a filament and terminal clavate zoos- 

 porangium are produced, from which actively moving zoospores 

 of ovate form are liberated, until all the material of the 

 chlamydospore is used up. This enclosed form of zoosporan- 

 gium — so unlike the usual one of the plant — strongly suggests 

 the genus Saproleg7iia^ to which Lcptoleg7iia is allied by the 

 diplanetism of its zoospores. 



