208 CONFERVACEsE. PART n. 



apparently so different, it results from the subdivision 

 of the cell which produces the bud. 



The ConfervacesB are generally reproduced by zoo- 

 spores. In most cases the endochrome within a cell 

 divides itself into numerous segments, each of which 

 becomes a minute zoospore, and escapes into the water 

 through a rupture in the cell wall. This is the case in 

 a very graceful genus of Confervse, of which the Chseto- 

 phora elegans is a species. It consists of filamental 

 strings of cells, ending in a capillary bristle, with lateral 

 branches like narrow fronds. It is reproduced by zoo- 

 spores. One half of each zoospore is round, opaque, 

 and full of matter ; the other half hyaline, and tapering 

 to a beak furnished with four cilia. It frequently happens 

 in this genus of Confervacese, where the filaments are 

 divided at equal distances into 

 little joints or compartments, that 

 the zoospores issue from the ter- 

 minal cell first, then from the next, 

 and so on in succession till the 

 upper part of the branch is left 

 empty, while the lower part is still 

 forming zoospores. After moving 

 in water for a time, the zoospores 

 Fig. is. zoosporea. retreat to a shady place, fix them- 

 selves to some substance, and begin 

 to grow. These plants rapidly cover a large surface of 

 water; for each individual cell may produce 100 zoo- 

 spores, and as the development and dissemination of 

 them continues during the whole summer, one plant 

 may yield an enormous number. 



The Sphseroplea annulina is a rare and very remark- 

 able Conferva, whose cinnabar-coloured spores make the 

 surface of the water in which it floats, like a pool of 

 blood. It has no root, being merely a filament with 

 capillary extremities, formed of elongated cells joined 



