Mr. H. J. Carter on Difflugia pyriformls. 261 



refractive cells might be "ovules"), it seems to me now that 

 they might also be considei'ed as analogous to the refractive 

 granules of Spongilla, &c. (that is, of an amylaceous composi- 

 tion), which, with the chlorophyll-vesicles of Euglena, would 

 then constitute just as much a part of this and all similar or- 

 ganisms as the chlorophyll-cells and starch-granules have been 

 shown to do of the body of Difflugia pyriformis. 



Lastly, when we extend this analogy to the Euglena, &c., it 

 passes us on to Spirogyra, CEdogonium, and the composition of the 

 contents of the cells of all the Confervoid Algse, where we find 

 all these refractive granules are actually composed of genuine 

 starch, as much as in the common vegetable cell. 



Resume. — This article is to show — 



1. That chlorophyll-cells exist in the body of Difflugia pyri- 

 formis as part of its organization. 



2. That starch-granules form part of its products. 



3. That the tests conjugate. 



4. That, apparently after this conjugation, when the body of 

 the Difflugia is densely charged with chlorophyll-cells and starch- 

 granules, the nucleus becomes charged with spherular, refractive, 

 homogeneous bodies, which appear to be developed in the proto- 

 plasm that lines (?) the nucleus. 



5. That the spherules pass from the nucleus into the body of 

 the animal, and there, becoming granuliferous, so increase by 

 duplicative division as to form the chief bulk of the whole 

 mass, while the chlorophyll-cells have entirely disappeared, and 

 the starch-granules have become more or less diminished in 

 number. 



It now remains to be shown whether the granuliferous cells 

 become polymorphic and ciliated, like the spherules in the Rhizo- 

 podous cell of Nitella, and, finally, whether they pass into young 

 Difflugia, — for which purpose I have collected a great many of 

 the tests, both green and colourless, and have placed them aside 

 for observation. 



The first question is thus answered : — 



Since the above was written, the bottom of a watch-glass, 

 in which four of the colourless specimens were placed with a 

 little water four days ago, has become covered with granuli- 

 ferous cells of the same size and appearance as those peculiar to 

 the colourless specimens, but with the following differences, 

 viz. that they are all provided with a cilium (perhaps two) ; 

 most are fixed to the watch-glass, and retain their globular 

 form ; others are swimming about by means of their cilium ; 

 many of the fixed globular forms are altering their shape by 

 becoming polymorphic ; and some have lost their cilium, and 



