110 PRTNGSHEIM, ON THE 



the lateral Avails become euonnously distended, then break up 

 in an irregular mauuerj and allow the spores to escape. Con- 

 sequently the cells are very soon disunited, and ail appearance 

 of branches disappears at the same time. The liberated spores 

 spread themselves in all directions aroimd, but they remain 

 immersed in a mucus -which envelops the whole plant, and 

 prevents their dispersion. I have observed these particular 

 circumstances as much in the monospore cells as in those 

 Avhich engender from two to four reproductive bodies. 



The fertile cells in Stigiodonium and Chcetoplwra Endivioe- 

 folia, constantly produce from two to four spores. The 

 branches constituted by these cells, undergo different trans- 

 formations from those Ulothrlv and Draparnaldia. The 

 mother-cells grow rapidly, and are sensibly enlarged in a 

 transverse direction ; their surface becomes uneven from a 

 kind of granular secretion ; they remain soldered to one 

 another, and do not allow the spores that they contain to 

 escape. But, in a short time, the contiguous walls, those 

 forming the septa of the braucli, are detached from the ad- 

 jacent or lateral distended walls, and quitting their oi'iginal 

 position, mix with the spores. The branch, consequently, 

 entirely loses its articulated appearance, and is changed into a 

 large irregular sac, in which the spores and the remains of 

 the septa are confusedly intermingled. 



The fructiferous plantules of Vhoitophora eiidiviwfoUa, are 

 easily distinguished even by the naked eye, from their 

 crowded appearance, diminutive form, and oljscure colour, 

 from the individuals which bear zoospores, and with vrhich 

 they are generally found mixed. Similar external differences 

 characterise also amongst the Draparnaldiaj those indivi- 

 duals which generate hypnosporcs from those better known 

 which alibrd zoospores. 



Setting out with this idea, that the hypnospores of the Dra- 

 parnaldiaj wxre zoospores, I determined to discover, if possi- 

 ble, and to observe the transformations of their reproductive 

 bodies into hypnospores ; but I only siACceeded after having 

 convinced myself by the study of Draparnaldia glomerata, 

 the cells of which allow their spores to escape, that these 

 hypnospores proceed from zoospores which have returned to 

 a state of repose. These observations also afforded the inter- 

 pretation of those unusual forms of hypnospores which I had 

 previously seen, mixed with the regularly rounded hypno- 

 spores. 



The zoospores of Draparnaldia glomerata, -which change 

 into chronispores^ are exactly like those zoospores known in 



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