OF THE PHYTOZOA. 167 



cell, filling up a more or less considerable portion of this (XIX. 39), while in 

 the polar view they form only a circular wreath. In some instances the 

 proper green body of the primordial cells is only shortly cylindrical ; but it 

 becomes elongated at both ends into long beaks which reach almost to the 

 poles, and give each primordial cell something of the shape of the Closterium 

 setaceum figui^cd by Ehrenberg. In this case the whole resembles a sphere 

 suiTounded by eight green bands placed in meridians and swollen only in the 

 equatorial region. But even in this veiy frequently occuiTing preponderating 

 development of the one dimension, the cilia of each primordial cell are sent 

 out from the middle of its shorter axis ; and when the primordial cells appear 

 projected in a zone, in the equatorial view, the motile cilia are visible only at 

 four points of the diameter. 



" The primordial cells are very frequently developed unequally in the two 

 hemispheres of the envelope-cell ; they are not then divided into two equal 

 halves by the equator of the envelope -cell, but show themselves crowded 

 principally into one hemisphere, which they almost fill ; and they reach almost 

 to the pole there, while they occupy but a far smaller portion of the other, 

 which consequently appears in greater paii: colouiless. In such a case the 

 primordial cells almost touch with one end, while they diverge widely at the 

 other, and thus they look like a kind of basket composed of eight pieces, like 

 the gaping dental apparatus of a Chilodon. 



•' Besides the two cilia which pass out from each primordial cell, through 

 the orifices of the envelope-cell into the water, the former very frequently 

 send out other prolongations, which however do not perforate the envelope- 

 cell. These are colourless mucilaginous Jilaments, going out from each pri- 

 mordial cell, especially from the ends of their longer axis, and which hence 

 present themselves especially clearly in the equatorial view. The ends of the 

 primordial cells are mostly not green but colourless, and elongated into numer- 

 ous, likewise colourless, broader or thinner bristle-like processes, which run out 

 like rays in all directions, are often ramified, and are attached to the inside of 

 the envelope-cell, without however perforating it (XIX. 39). If these fila- 

 ments are much developed, they form a proper network, w^hich maiataitis each 

 primordial cell floating in the common envelope. The extremities of the pri- 

 mordial cells are also frequently divided dichotomously into colourless muci- 

 laginous bands, which again branch into radiating filaments and thus produce 

 the most wonderful forms. These colourless filiform prolongations of the 

 primordial cells may also be seen in the polar view, stretching in aU direc- 

 tions, and giving the total structui^e a most strange aspect, almost similar to 

 that of a Xanthidium. 



" In the internal organization of the primordial cells, all that can be made 

 out is a green-coloured softish substance, of which they are composed, and in 

 which numerous delicate granules or points are imbedded. "Wlien the pri- 

 mordial cells are actively vegetating, they are of a transparent vivid green ; 

 but the coloiu' exhibits various tints : in the youngest conditions it is purer, 

 more yellowish green, less obscured by dark points ; in the largest forms, on 

 the contrary, the contents appear brownish green and opake, with the dark 

 granules multiphed to such an extent, that the whole almost loses its transpa- 

 rency. In the middle of the primordial cells are found tiuo larger, nucleus-UTce 

 vesicles, mostly symmetrically placed ; and these examined separately appear 

 annular, so that tliey possess an internal cavity ; iodine colours them remarkably 

 dark, with a ^dolet tinge (XIX. 39). The centre of each primordial cell is 

 frequently occupied by a lighter circular space, which however does not vanish 

 periodically, and therefore cannot be regarded as a contractile vesicle (XIX. 38). 



" The primordial cells are not surrounded by any special rigid membrane; 



