ON PELOMTXA VIRIDIS. 361 



regarded as an entoplastic product of the protoplasmic activity 

 rather than as any portion of the protoplasm itself. The 

 chlorophyllogenous stroma occupying the vesicles of P. 

 viridis is no more entitled to be regarded as a portion of the 

 protoplasm than are chlorophyll bodies or oil-globules, or any 

 other structures ordinarily spoken of as protoplasmic contents. 

 It is, of course, the presence of the chlorophyll which leads me 

 to this conclusion. If I am correct in regarding these chloro- 

 phyllogenous structures as the homologues of the vesicles 

 found in other protoplasms, the condition of P. viridis lends 

 strong support to Biitschli's theory that the plasma is the sub- 

 stance which forms the envelopes of these vesicles only, or, 

 as Biitschli has termed it, the substance forming the scaffold- 

 ing of a honeycomb (Substanz des Wabengerusts), and does not 

 include their contents (Wabeninhalt). 



The structure of P. viridis is, on the other hand, rather 

 opposed to Butschli's most recent views with regard to proto- 

 plasmic movements. If I understand rightly from the abstract 

 available to me, Biitschli believes that a movement starts by the 

 bursting of some vesicle, a phenomenon which would naturally 

 escape observation in ordinary protoplasm, but of which, if 

 it is constantly occurring, I should surely have seen something 

 in a protoplasm whose vesicular contents are brightly coloured. 



With regard to the homology which I have assumed to exist 

 between the vesicles of ordinary protoplasm and those of 

 P. viridis with their chlorophyllogenous contents, it is quite 

 clear, in the first place, that these are the structures which 

 render the protoplasm of P. viridis vesicular. There exist, 

 it is true, in addition to them a number of vacuoles of varying 

 sizes, but of these there are after all comparatively few, and if 

 they alone were present the protoplasm could not be called 

 vesicular. There is no evidence that these vacuoles contain 

 any substance other than water. 



We can undoubtedly distinguish in P. viridis between two 

 varieties of non-contractile fluid-containing spaces (nicht con- 

 tractile Fliissig-Keitsriiume), the vacuoles containing water 

 and the vesicles having chlorophyllogenous contents. 



