DEVELOPMENT OF PROTOCOCCUS : STILL CONDITION. 247 



red ; and their red form has received the distinguishing appellation 

 of Hcematococcus. Very commonly the red colouring- matter forms 

 only a central mass of greater or less size, having the appearance of 

 a nucleus (as shown at e) ; and sometimes it is reduced to a single 

 granular point, which has been erroneously represented by Prof. 

 Ehrenberg as the eye of these so-called Animalcules. It is quite 

 certain that the red colouring-substance is very nearly related in 

 its chemical character to the green, and that the one may be con- 

 verted into the other : though the conditions under which this 

 conversion takes place are not precisely known. In the still form 

 of the cell, with which we may commence the history of its life, we 

 find a mass of Endochrome, consisting of a colourless Protoplasm, 

 through which red or green-coloured granules are more or less uni- 

 formly diffused : on the surface of this endochrome the colourless 

 protoplasm is condensed into a more consistent layer, forming an 

 imperfect Primordial Utricle ; and this is surrounded by a tolerably 

 firm layer, which seems to consist of Cellulose or of some modifica- 

 tion of it. Outside this (as shown at a), when the ' still ' cell is 

 formed by a change in the condition of a cell that has been previously 

 1 motile,' we find another envelope, which seems to be of the same 

 nature, but which is separated by the interposition of aqueous 

 fluid ; this, however, may be altogether wanting. The multiplica- 

 tion of the 'still' cells by self -division takes-place as in Palmoglcea: 

 the endochrome, enclosed in its primordial utricle, first undergoing 

 separation into two halves (as seen at b), and each of these halves 

 subsequently developing a cellulose envelope around itself, and un- 

 dergoing the same division in its turn. Thus 2, 4, 8, 16 new cells 

 are successively produced ; and these are sometimes set-free by the 

 complete dissolution of the envelope of the original cell ; but they 

 are more commonly held-together by its transformation into a gelati- 

 nous investment, in which they remain imbedded. Sometimes the con- 

 tents of the primordial utricle subdivide at once into four segments 

 (as at D), of which every one forthwith acquires the characters of an 

 independent cell ; but this, although an ordinary method of mul- 

 tiplication among the ' motile ' cells, is comparatively rare in the 

 'still' condition. Sometimes, again, the cell-contents of the 'still' 

 form subdivide at once into eight portions, which, being of small 

 size, and endowed with motile power, may be considered as 

 Zoospores ; it is not quite clear what becomes of these ; but 

 there is reason to believe that some of them retain their motile 

 powers, and, after increasing in size, develope an investing cyst, 

 like the free primordial utricles to be presently described ; that 

 others produce a firm cellulose envelope, and become ' still ' cells ; 

 and that others (perhaps the majority) perish without any further 

 change. 



189. When the ordinary self- division of the 'still' cells into 

 two segments has been repeated four times, so as to produce 16 

 cells — and sometimes at an earlier period, — the new cells thus 



