730 MICROSCOPIC FORMS OF ANIMAL LIFE PROTOZOA 



cysts are composed 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 protoplasm breaks up into two or four 

 ' tetraspores ' (fig. 569, 6, d) ; these escape by openings in the cyst 

 (fig. 568, C), and soon take the spherical form, emitting very slender 

 pseudopodial filaments (figs. 568, D, 569, e) like those of an Actino- 

 phrys, but possessing neither nucleus nor contractile 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 

 contracting again into minute spheres. When the V. spirogyrce 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 endoplasm, carrying with it the chloro- 

 phyll-granules it includes, passes slowly into the body of the Vam- 

 pyrella. 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 w r hich it has ingested 

 become diffused through the body, but gradually cease to be distin- 

 guishable, the protoplasmic mass assuming a brick-red colour. The 

 first layer it exudes to form its cyst is the outer or nitrogenous invest- 

 ment, within which the cellulose layer is afterwards formed. Jhe V, 

 yomphoneniatis in like manner creeps over the stems and branches of 

 the Gomphonema (fig. 569, e), adapting itself to the form of its sup- 

 port ; and as soon as it has reached one of the terminal siliceous cells 

 of the diatom, it extends itself over it so as completely to envelop 

 the cell in a thin layer of protoplasm. From the surface of this a 

 number of fine pseudopodia radiate into the surrounding water (f) ; 

 whilst another portion of the protoplasm finds its way between the 

 two siliceous valves into the interior, and appropriates its contents. 

 The valves, when emptied, break off from their support, and are cast 

 out of the body of the Vampyrella, which soon proceeds to another 

 6fompkonema-ce\\ and plunders it in the same manner. After thus 

 ingesting the nutriment furnished by several cells, and acquiring its 

 full size, it passes, like V. spirogyrce, into the encysted condition, 

 to recommence after a period of quiescence the same cycle of 

 change. Mr. Bolton discovered near Birmingham, and Professor Ray 

 Lankester described, a form allied to Vampyrella Archerina Boltoni 

 which is remarkable for being chlorophyllogenous ; this species 

 presents another interesting peculiarity : ' Groups of ghost-like 

 outlines corresponding to chlorophyll -corpuscles and their radiant 

 filamentous pseudopodia, entirely devoid of any substance,' were 

 observed, and were compared to the numerous cellulose chambers 

 which are secreted and abandoned by the protoplasm of Chlamy- 

 (lomyxa. 



Intermediate between the foregoing and the ; reticularian ' rhizo- 

 pods to be presently described, is another simple protozoon dis- 



