4: THE MICROSCOPE AND ITS REVELATIONS. 



dition as a minute brick-red sphere attached to the filaments of the Con- 

 jugate Spirogyra: whilst another (Fig. 281, a, a) similarly attaches itself 

 to the branches of Gomphonema ( 294). The wails of the cysts are com- 

 posed of two membranes; of which the interior gives the characteristic 

 reaction of cellulose, whilst the softer external layer is nitrogenous. 

 After remaining some time in the quiescent condition, the encysted pro- 

 toplasm breaks up into two or four ( tetraspores ' (Fig. 281, b, d)', these 

 escape by openings in the cyst (Fig. 280, c); and soon take the spherical 

 form, emitting very slender pseudopodial filaments (Figs. 280, D, 281, B) 

 like those of an Actinoplirys, but possessing neither nucleus nor contrac- 

 tile vesicle. In this condition they show great activity; moving about in 

 search of the special nutriment they require, drawing themselves out in 

 strings and fine filaments which tear asunder and again unite to send off 

 branches and form fine fan-like expansions, and these occasionally contract- 

 Fig. 280. 



Vampyrella spirogyrce, as seen at A sucking-out contents of Spirogyra-cell ; at B in encysted 

 condition, the cyst a inclosing granular protoplasm b; at c, division of contents of cyst into tetra- 

 spores, of whicn one is escaping in the amoeboid condition, to develop itself into the adult form 

 shown at D. 



ing again into minute spheres. When the V. spirogyrm is watched in 

 water containing some filaments of Spirogyra, it may be seen to wander 

 until it meets one of these filaments, to which, if it be healthy and loaded 

 with chlorophyll, it attaches itself. It soon begins to perforate the wall 

 of the filament; and when the interior of this has been reached, its endo- 

 plasm, carrying with it the chlorophyll-granules it includes, passes slowly 

 into the body of the Vampyrella. In this manner, cell after cell is 

 emptied of its contents; and the plunderer, satiated with food, resumes 

 its quiescent spherical form to digest it. The chlorophyll granules which 

 it has ingested become diffused through the body, but gradually cease to 

 be distinguishable, the protoplasmic mass assuming a brick-red color. 



