CH^ETOPHORACE^E. 71 



plants in any pool or pond, one of the species of Con- 

 ferva, C. flocculosa, is almost sure to be met with. 

 On close inspection with the naked eye, the green 

 filaments of which it consists are just visible, as ex- 

 tremely fine, soft, silky threads ; and, under a high 

 power of the microscope, the filaments are seen to be 

 uiibranched, and composed of a single row of cells 

 (PL V. fig. 1), or joints, as they are called in technical 

 works ; these are 2 or 3 times as long as broad. In 

 some specimens the joints are swollen, so as to present 

 a rounded outline. In another common species, C. 

 bombydina, the filaments are somewhat more slender, 

 and the joints are from 3 to 5 times as long as broad. 



Cladoph'ora crispdta. This Confervoid forms large, 

 entangled, dull-green masses, composed of branched, 

 tufted, somewhat rigid and coarse filaments. It is 

 often a troublesome overrunner of the fresh-water 

 vivarium. The filaments are composed of thick- walled 

 cells (PL V. fig. 6), from 4 to 6 times as long as 

 broad, and often containing minute starch-granules. 



The Confervacese have two modes of reproduction. 

 The first of these consists in the division of the endo- 

 chrome of the joints into a number of distinct seg- 

 ments, each of which becomes furnished at one end 

 with two very slender cilia (PL Y. fig. 6 a). After a 

 time, these ciliated bodies, which are called zo'ospores 

 (wov, animal, airopd, seed) or gonid'ia (701/77, seed, 

 eZSo?, resemblance), escape from the cells either by 

 their rupture or through a papillary orifice, and swim 

 about in the water, ultimately losing their cilia and 

 growing into cells resembling those of the parent 

 plant. In the second method, which occurs, for in- 

 stance, in Conferva bombycina, certain of the joints 

 enlarge so as to become rounded or inflated ; their 

 endochrome then becomes coated with a new cell- wall, 

 and so forms a spore, which subsequently escapes 

 from the cell and germinates. 



:. Draparnal 'dia glomerdta forms 



