AND GERMINATION OF ALG^. 133 



formed, to act the part of an impregnating apparatus. And 

 connected with this supposed diversity in the mode of im- 

 -prcgnation is probably the difference observable in the mode 

 of germination. ; fo?' the germination of the quiescent spores in 

 Bulbocha:te differs very essentially from that of spores of 

 Vaucheria. 



The curious development of the quiescent spores of the 

 former plant is thus described by the author. 



The thick-walled, wholly red spore became green at the 

 border, the innermost layer of the cell-wall expanded and 

 burst through the outer layers and the membrane of the spo- 

 rangium. Thus the spore escaped from the sporangium covered 

 only by the innermost thin layer of the cell-wall, whilst the 

 ruptured walls either opened out like two lids (fig. 31), or the 

 upper portion was elevated upon the escaping spore (fig. 30). 

 This liberated cell in a few hours was elongated into an ovoid 

 corpuscle (figs. 32, 33), whose contents shortly afterwards 

 were divided by successive scissions into four parts, lying one 

 behind the other (fig. 33). 



In one or other of these portions of contents might now be 

 perceived a lateral, clear space (fig. 33), whilst the membrane 

 surrounding the four bodies thus constituted became more and 

 more expanded, lost its consistence, and swelled out into a 

 kind of jelly. At the same time a faint movement was per- 

 ceptible in the four reddish-green bodies, becoming more and 

 more marked as the membrane expanded. The structure of 

 the bodies was now sufficiently obvious ; each exhibited a 

 clear space at one end, aiound which was a crown of cilia 

 (fig. 34) ; they mov^ed about as far as the space would allow 

 with great activity, with a continued vibration of the cilia, and 

 an uninterrupted turning on their axis. 



Thus in the interior of the quiescent spore four zoospores 

 were produced, which presented precisely the same structure, 

 and were of the same size as the usual zoospores of JBidhochcete, 

 from which they differed merely in the circumstance that they 

 contained, at any rate some of them, a red oil, similar to that 

 with which the quiescent spores are filled. 



These zoospores, when liberated from the suriounding 

 vesicle, attached themselves and germinated. This production 

 of four zoospores within the quiescent spore of Bulbochcete^ 

 recalls the similar process in Chlamidococcus pluvialis, and 

 shows that the quiescent forms of the VolvocincB should be 

 regarded simply as quiescent algan spores resulting from 

 sexual impregnation. 



In various species of Coleochate the formation of zoospores, 



