ZOOLOGICAL AND BOTANICAL ASSOCIATION. 107 



and well-defined outline. They are, I should think, granules of chloro- 

 phyll, of a firmer texture, but of a lighter colour, than the remaining 

 endochrome. That they might occasionally contain starch is, I suppose, 

 probable. I tried the application of iodine, but without being able to 

 see the characteristic tint of starch, — the whole plant being stained a 

 yellowish-brown, while the central corpuscles became very much darker 

 than the other part of the endochrome. At each extremity of the joint 

 the endochrome becomes more or less retracted from the end of the " pri- 

 mordial utricle," leaving a clear space, which, in cells just after division, 

 is very small, but which afterwards becomes greatly larger. Within 

 this clear space several active granules may be seen in constant agitation, 

 like those in Closterium, Docidium, &c, though there does not appear 

 any special chamber, as it were hollowed out of the endochrome, con- 

 taining the moving granules, as in those genera. These were more nume- 

 rous and more evident in the fresh specimens some five or six months 

 ago, when I first noticed this plant, than they are in specimens gathered 

 during the winter. Of these active granules I have remarked sometimes 

 one or two in some specimens notably larger than the others, and I have 

 noticed the granules continue their active motion in the water for some 

 time after being set free by the forcible fracture of the cell, as will pre- 

 sently be again alluded to. If the joint under examination be now caused 

 to make a quarter of a revolution on its long axis, the narrow or side 

 view of the compressed endochrome becomes turned towards the observer, 

 and consequently presents a different aspect (see Fig. 2). The outline 

 of the endochrome, now brought to view, is seen to be somewhat un- 

 dulatory or waved, owing to the mass of endochrome closely embracing 

 tho central row of light-coloured corpuscles which are still distinctly 

 visible, so that at the regular intervals of their occurrence they form 

 slight protuberances or distentions of the compressed band of endochrome, 

 which at this edge view does not fill more than about a third of the 

 diameter of the celL I have sometimes noticed (but rarely, however) 

 each half of the endochrome to be turned a different way with regard 

 to the other, or at right angles, that is, one half presenting the broad 

 view simultaneously with the other showing the waved, compressed, 

 lateral view, which conditions were of course reversed on the joint being 

 caused to turn longitudinally one quarter of a revolution. I have once 

 noticed one half of the band of endochrome to be, as it were, twisted upon 

 itself. The transparent pale space, due to the suspension of the endo- 



