DEVELOPMENT AND MULTIPLICATION OF CONFERVA. 331 



Fig. 153. 



surface, by a process of budding ; which, notwithstanding its 

 difference of mode, agrees with that just described in its essential 

 character, being the result of the subdivision of the original cell. 

 A certain portion of the primordial utricle seems to undergo in- 

 creased nutrition, for it is 

 seen to project, carrying the 

 cellulose envelope before it, 

 so as to form a little pro- 

 tuberance ; and this some- 

 times attains a considerable 

 length, before any separa- 

 tion of its cavity from that 

 of the cell which gave origin 

 to it begins to take place. 

 This separation is gradually 

 effected, however, by the 

 infolding of the primordial 

 utricle, just as in the pre- 

 ceding case : and thus the 

 endochrome of the branch- 

 cell becomes completely 

 severed from that of the 

 stock. The branch then 

 begins to elongate itself by 

 the subdivision of its first- 

 formed cell ; and this pro- 

 cess may be repeated for a 

 time in all the cells of the 

 filament, though it usually 

 comes to be restricted at last Process of cell-multiplication in Con- 

 in thp terminal pell The ferm 9^nerata .—a, portion of filament 

 to tne terminal ceil, ine with incomplet e separation at a, and 

 Confervacece multiply them- complete partition at 6 ; b, tlie separa- 

 selves by Zoospores, which tion completed, a new cellulose partition 

 are produced within their being formed at a; c, formation of addi- 

 ii j + i f tional layers of cellulose wall c, beneath 



cells, ana are then set-tree, ^e muc0 us investment d, and around 

 just as in the Ulvaceaa the primordial utricle a, which encloses 

 (§ 241) ; in most of the the endochrome b. 

 genera the Endochrome of 



each cell divides into numerous zoospores, which are of course very 

 minute ; but in (Edogonium — a fresh-water genus distinguished 

 by the circular markings which form rings round the extremities of 

 many of the cells, and by many interesting peculiarities of growth 

 and reproduction* — only a single large zoospore is set free from each 

 cell ; and its liberation is accomplished by the almost complete 

 fission of the wall of the cell through one of these rings, a small 

 part only remaining uncleft, which serves as a kind of hinge 



* See the account of these processes in the "Micrographic Dictionary," 

 2nd Edit. p. 501. 



