266 THE MICROSCOPE. 



eight days, under favourable circumstances, 16,777,216 

 families may be formed from one resting-cell of Stephano- 

 sphaera. In certain of the cells, and at particular periods, 

 the remarkable amaboid bodies (Plate 1, No. 24 c), have 

 been noticed. There is a marked difference between 

 Stephanosphaera and Chlamydococcus, " for, while in the 

 latter the individual portions of a primordial cell separate 

 entirely from one another, each developing its own enve- 

 loping membrane, and ultimately escaping as a unicellular 

 individual ; in the former, on the other hand, the eight 

 portions remain for a time united as a family." * 



The simplest forms of vegetable life are met with in the 

 Confervoids, which are as interesting as they are in- 

 structive to the microscopist. The confervas consist of 

 unbranched filaments composed of cylindrical cells, placed 

 end to end; their reproductive process is carried on by 

 zoospores produced from the cell contents. The fresh- 

 water genera are principally of a yellowish green colour ; 

 sometimes presenting a striated appearance, which has 

 given rise to a supposition that their filaments are spiral. 

 They are indeed plentifully distributed both in fresh and 

 salt-water. 



Oscillatoriacece. The study of the structure of the Oscil- 

 latorice is particularly interesting, from the fact that we 

 may not unreasonably expect to find in it a key to the 

 singular motion from which they received their generic 

 name, and which now, for more than a century, has 

 formed an object of curiosity and interest to the micro- 

 scopist, without having received, as yet, a satisfactory 

 explanation. 



The following different tissues are observable in the true 

 Oscillatorice : 1, An outer inclosing sheath ; 2, A special 

 cell-membrane, with its contents ; and 3, The axis, or pith, 

 of the filament. 



" The filaments of certain species are inclosed in sheaths 

 or continuous tubes, never showing any cross-markings 

 corresponding to the striae of the filament ; they are clearly 

 composed of a kind of cellulose, although they remain 

 unaffected by iodine. In other species, these tubes are 



* See an interesting paper by F. Currey, F.R.S. Journal of Microscopical 

 Science, vol. vi. 1858, p. 131 ; also by Mr. Wm. Archer, vol. v. 1865, p. 116 



