26 Mr. H. J. Carter on Freshwater RMzopoda 



in the same animal ; and I have already stated that the spherules 

 of the nucleus, after passing into the body of D. pyriformis, 

 ultimately appear in the watch-glass with ciliated polymorphic 

 bodies, whereby we may fairly infer that the same changes take 

 place in those of D. compressa. What, then, becomes of the 

 " reproductive cells " in D. compressa ? Now, assuming, as we 

 have done, that the reproductive cells in D. pyriformis were 

 mistaken for large starch-granules, and remembering also not 

 only that the spherules were ciliated, but also that Amoebce much 

 larger in size were among the contents of the watch-glass (PI. I. 

 fig. 4 «, h), which were inferred to come from the colourless 

 specimens of D. pyriformis, in which the spherules had passed 

 into the body of the animal, is it not worthy of consideration 

 whether the latter (that is, the Amoeba) may not have come from 

 the reproductive cells ? and, therefore, whether the spherules of 

 the nucleus may not bear the relation of spermatozoids to these 

 reproductive cells ? If so, too, in some instances, the granula- 

 tion of the nucleus may take place in one, and the formation of 

 the reproductive cells (from a larger subdivision of the nucleus) 

 in another individual — thus rendering the species dioecious ; 

 while others may be both monoecious and dioecious. It 

 would be easy for impregnation to take place in the body of the 

 Difflugia, where both the spherules of the nucleus and the repro- 

 ductive cells might come together in a preeminently plastic state 

 for their union, although it be true that in many instances the 

 procreative elements of other organisms eliminate themselves 

 from the parent and get into the water before this act takes 

 place : at the same time here it must occur quickly, or the forma- 

 tion of a pellicle over the surface of the protoplasm of the germ- 

 cell or sperm-cell (which it does not appear to be in the power 

 of either to control) inevitably defeats the process. 



There is another question also which I have not yet been able 

 to determine, viz. whether or not the chlorophyll-cells in D. pyri- 

 formis and the brown cells in D. compressa are not identical with 

 those bodies in the Amoeba, &c., which I have termed " gran- 

 ules" (Annals, ser. 3. vol. xii. p. 33 &c.). In the amoebous cell of 

 Spongilla they are frequently of a bluish emerald-green colour 

 under the microscope, and, in some instances, appear to impart 

 the green colour to the mass. Again, in Amoeba princeps, &c., 

 they frequently pass into crystalloids ; while I have seen and 

 figured them also in the pseudopodia of Diffiugia tricuspis, Cart. 

 (Annals, ser. 2. vol. xviii. pi. 7. fig. 80), and in those of Arcella 

 vulgaris, Ehr. Yet in those of D. pyriformis and D. compressa I 

 have never seen anything but a dense number of fine granules, 

 which look like those with which the sarcode is charged, and 

 to which I have given the name of "moleculse." Hence I 



