254 



MICROSCOPIC FORMS OF VEGETABLE LIFE. 



commonly regarded as an Animalcule, its different states having 

 been described under several different names. 



153. In the first place, the color of these cells varies consider- 

 ably; since, although they are usually green at the period of 

 their most active life, they are sometimes red; and their red 

 form has received the distinguishing appellation of Hcematococcug. 

 Very commonly the red coloring matter forms only a central 

 mass of greater or less size, having the appearance of a nucleus 

 (as shown in Fig. 68, 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 coloring substance is very nearly related in 



FiQ. 68. 



Various phases of development o{ Protococcus pluvialis: — a, an encysted ceil, whieh has passed 

 into the " still" condition ; b, division of a " still" cell into two ; c, another mode of division into two, 

 each primordial vesicle having developed a cellulose envelope around itself, whilst yet within the 

 original cell; D, division of an encysted cell into four; e, division of an encysted cell into eight; F, 

 division of an encysted cell into thirty-two segments ; G, motile gonidia (zoospores) after their escape 

 from the original cell; h, a primordial utricle, without cellulose envelope, furnished with two cilia; 

 1, a similar primordial utricle, with distinct cellulose envelope, and threads of protoplasm extending 

 towards it; k, an encysted primordial utricle, pointed at both ends, and furnished with two cilia; L, 

 an encysted primordial utricle, of which nearly half is composed of a colorless granular substance, 

 enclosing a red body resembling a nucleus. 



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

 converted into the other; though the conditions under which 

 this conversion may take place are not precisely known. In the 

 still form of the cell, with which we may commence the history 



cells throughout its whole course.'' Probably he would have found the glass tube cells 

 represented in Fig. 65, if he had been acquainted with them, to answer his purpose just 

 as well as these specially constructed vessels. 



