196 GENERAL HISTOEY OF THE INFrSORIA. 



latter had passed to the state of repose." This view of the affinity of Chlo- 

 rogonium accords with that which Weisse indicates in the statement that this 

 genus and Glenomorur,i tingens (species of Ehrenberg's family Monadind) are 

 but two phases of the same being. 



Weisse has appended some remarks to the preceding account by Schneider 

 Midi. Archil', 1856, p. 160). He says that he mtnessed the revivification 

 of encysted Cldorogonia (a phaenomenon unnoticed by Schneider) on placing 

 some cysts, collected the preceding year, in water. The reddish and pre- 

 viously spherical cysts were seen to gradually lose their regular outhne by 

 the elongation of one end, and thereby to acquire an ovate form. After a 

 short time the naiTower end of the cyst ruptured, and a very thin-walled 

 vesicle protruded through the rent : whilst this took place, a movement of 

 the contents of the cyst became evident ; and after a while several constric- 

 tions appeared, which extended deeper until they di\ided the whole into four 

 portions. For a time the protniding sac elongated itself more and more, but 

 ultimately, owing to the pressure within it of the moving particles, gave way 

 and allowed their exit. The escaped sections were, as a rule, of pretty uniform 

 sizes, but had not the remotest resemblance to the mature Chlorogonium, and 

 indeed might have readily been assigned to another group of beings. Their 

 figure was elongated, irregular, and often triangular, on fii^st escaping from 

 the cyst ; they were also flexible in every direction, and of a dusky brown 

 colour. After dispersion, on reaching the margin of the drop of water, they re- 

 sumed a globular shape, changed to a rusty red colour, and after a few hoiu's 

 assumed the appearance of clear-green spindle or bodo-shapcd organisms. 

 Between their evolution from the cysts and their development into the form 

 of ChJor^ogonium, two hours, less or more, intervened. This di^^sion into four 

 segments, representing four new beings of Chlorogonium progressively evolved, 

 apparently without actual metamorphosis, may be rightly esteemed an act of 

 reproduction by macrogonidia, whilst the breaking up of the organism into a 

 multitude of zoospores, as previously described by Weisse, is a process of re- 

 production by microgonidia. 



Kature of Astasi^a. — It is with certain members of this family that 

 Thuret pointed out (Ann. iSc. Nat. 1850, xiv.) the close resemblance to the 

 zoospores of Algae, amoiinting, as far as outward appearances indicate, to 

 actual identity. 



"This affinity," he says, ''is exhibited in the colour, form, in the number and 

 character of the ciliary filaments, in the contents, not excepting the coloui-ed 

 eye-speck, in the mode of self-fission, and also in the power of locomotion. 

 What is still more, both zoospores and Astasicca tend to the light, disengage 

 a gas, most probably oxygen, and emit a peculiar spermatic odour. However, 

 by continued watching the zoospores are seen to affix themselves to some body, 

 surrender their seeming animal life, and proceed to germinate, developing a 

 tissue similar to that of the plant which gave them birth. On the other hand, 

 the true Astasicva, if they attach themselves, it is but for a time, and no ap- 

 pearance of germination ensues. The closest similarity exists in the case of 

 the Chlamydomonas pidvisculus (Diselmis viridis, Duj.), and in a less degree 

 in the Euglence, .... In the form of the body, in that of the flabelliform ciha, 

 and in the disposition of those cilia, as also in the contents of the body, 

 the resemblance is complete. The movements of Diselmis are like those of 

 zoospores ; and, like them, they tend to the Hght. In one distinct species, or 

 rather, in a particular state of the same species, a very clear red spot is dis- 

 cernible, and a central globule, very hke in appearance to the amylaceous 

 granules so frequent in the cells of green Algae. These Infusoria appear to 

 act on the atmospheric air like Algae and the green parts of other plants, dis- 



