390 F. W. GAMBLE AND FREDEEICK KEEBLE. 



Nevertheless the phenomena of the green and colourless 

 cells of Convoluta are, so far as we know, not collectively 

 found in any known algJB. The absence of the cellulose coat, 

 for example, is, we believe, unique. Yet the knowledge of 

 the influence of saprophytic and parasitic life upon the struc- 

 ture and development of alga) is so scanty (Grintzesco, 1903) 

 that we can but hope that, when more complete investigations 

 have been made, light will be thrown on the nature of these 

 green cells of Convoluta. We conclude this section by 

 pointing out how the present research may give points of 

 departure for such work. 



We have seen that Haberlandt isolated green cells, main- 

 tained them in a hanging drop, and found that under these 

 conditions they ceased to divide and gradually disintegrated, 

 whence he concluded that apart from Convoluta the green 

 cells are incapable of existence. It is, however, clear from 

 the foregoing description (see also p. 53) that, when discharged 

 during oviposition, the green cells find themselves attached 

 to a mucilaginous capsule and surrounded by a richly proteid 

 substance. Under these circumstances their fate may be a 

 very different one from that which overtakes green cells 

 isolated in sea water. Hence Haberlandt's conclusion is only 

 true for the conditions of his experiment, and it is quite 

 possible that the green cells are but one phase in the life- 

 history, or one of the forms of vegetative growth of a 

 polymorphic organism (cf. Chodat, 1902). 



4. The Development of the Green Cells from 

 Colourless Predecessors. 



The researches of Geddes, von Gralf, and especially of 

 Haberlandt, have elucidated the chief features of the green 

 cells. Thus it is known that they form a single layer in the 

 outer parenchymatous zone, and that they consist of a naked 

 spherical or pyriforin protoplast, containing a usually single 

 chloroplast, a pyrenoid, and an cxcentrically placed nucleus. 

 Besides the rod-like masses of starch, varying amounts of a 



