GENE.RATION OF CONFERVACE^ AND CONJUGATEiE. 319 



apertures in the walls of certain other cells, within each of which 

 the endoclirome has coalesced into a globular mass ; over this 

 mass the antherozoids spread themselves, and seem to dissolve 

 away upon its. surface; and after this process has taken place, 

 the mass of endochrome acquires a firm envelope, and becomes 

 a "resting-spore," which, when set free by the rupture of the 

 parent cell- wall, germinates into a new plant. A curious vai'ia- 

 tion of this process is seen in (Edogonium ; for instead of the 

 antherozoids escaping freely from the "sperm-cells" which pro- 

 duced them, they are discharged en masse, included within a 

 capsule which is furnished with cilia, and which so resembles a 

 " zoospore" as to be easily mistaken for it ; and it is only when 

 this has attached itself, and has set free its contents by the fall- 

 ing off of a sort of lid, that the antherozoids are enabled to 

 perform their fertilizing office. The same thing happens in 

 some other Confervacese ; in which, however, the antheridial 

 capsules, being smaller than the zoospores, are distinguished as 

 microgonidia, whilst the latter are known as macrogonidia. The 

 offices of these different classes of reproductive bodies are only 

 now beginning to be understood; and the inquiry is one so 

 fraught with Physiological interest, and, from the facility of 

 growing these plants in artificial Aquaria, may be so easily pur- 

 sued, that it may be hoped that Microscopists will apply them- 

 selves to it so zealously, as not long to leave any part of it in 

 obscurity. 



199. The family Conjugatem agrees with that of the Gonfervacece 

 in its mode of growth, but differs from it in the plan in which 

 its generative process is performed ; this being accomplished by 

 an act of "conjugation," resembling that which has been de- 

 scribed in the simplest Protophytes. These plants are not found 

 so much in running streams, as in waters that are perfectly still, 

 such as those in 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 influ- 

 ence of solar light and heat. In an early stage of their growth, 

 whilst as yet the cells are undergoing multiplication by subdi- 

 vision, the endochrome is commonly diffused pretty uniformly 

 through their cavities (Fig. 109, a) ; but as they advance towards 

 the stage of conjugation, the endochrome ordinarily arranges, 

 itself in regular spirals (b), but occasionally in some other forms. 

 The act of "conjugation" usually occurs between the cells of two 

 distinct filaments, that 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 

 breaking down of the intervening partitions, so as to establish a 

 free passage between the cavities of the conjugating cells. In 

 some genera of this family (such as Mesocarpus), the conjugating 



