334 



FAMILY CONJUGATED. 



Physiological interest, and, from the facility of growing these plants 

 in artificial Aquaria, may he so easily pursued, that it may be hoped 



that Microscopists will apply 

 Fig. 154. themselves to it so zealously 



as not long to leave any part 

 of it in obscurity. 



251. The Family Conju- 

 gatece agrees with that of 

 Confervacece in its mode of 

 growth, but differs from it in 

 the plan on which its Gene- 

 rative process is performed ; 

 this being accomplished by an 

 act of Conjugation resembling 

 that which has been described 

 in the simplest Protophytes. 

 These plants are not found so 

 much in running streams, as 

 in waters that are perfectly 

 still, such as those of ponds, 

 reservoirs, ditches, or marshy 

 grounds ; and they are for the 

 most part unattached, floating 

 freely at or near the surface, 

 especially when buoyed-up by 

 the bubbles of gas which are 

 liberated from the midst of 

 them under the influence of 

 solar light and heat. In an 

 early stage of their growth, 

 whilst as yet the cells are 

 undergoing multiplication by 

 subdivision, the Endochrome 

 is commonly diffused pretty 

 uniformly through their cavi- 

 ties (Fig. 155, a) ; but as they 

 advance towards the stage of 

 conjugation, the endochrome 

 ordinarily arranges itself into 

 regular spirals (b), but occa- 

 sionally in some other forms. 

 The act of Conjugation usu- 

 ally occurs between the cells 

 of two distinct filaments that 



Sexual reproduction of (Edogonium 

 ciliatum :— 1, filament with two Oo- 

 spores in process of formation, the 

 lower one having two Andro-spores at- 

 tached to its exterior, the contents of 

 the upper one in the act of being ferti- 

 lized by the entrance of an anthero- 

 zoid set free from the interior of its 

 Andro-spore ; 2, free Antherozoids ; 3, 

 mature Oo-spore, still invested with 

 the cell-membrane of the parent fila- 

 ment ; 4, portions of a filament bear- 

 ing sperm-cells, from one of which an 

 Andro-spore is being set free ; 5, libe- 

 rated Andro-spore. 



happen to lie in proximity to 

 each other ; and all the cells of each filament generally take part in 

 it at once. The adjacent cells put forth little protuberances, which 

 come into contact with each other, and then coalesce by the break- 



