260 Mr. H. J. Carter on Difflugia pyriformis. 



the sponge-cells by the " vito-catalytie " influence of a thin film 

 of protoplasm with which they become surrounded. 



Now it seems to me that this thin film may be an expansion 

 of one of the " small granules " of the globular cell of the seed- 

 like body, and that these granules might have originated from a 

 granulation of the nucleus of the globular cells respectively ; for 

 certainly no trace remains of the nucleus, which as certainly existed 

 when the globular cell was in an active state. It must be un- 

 derstood here that the " granule " is viewed as a nucleus, or 

 centre of vitality, capable of developing a cell around itself in 

 the manner of the germ of the "cell" generally, which membrane 

 in this instance would be plastic and polymorphic, and therefore 

 become expansible into the thin film mentioned. 



In this way we should have a direct analogy between the 

 development of the amoebous cell, which, in its plurality, makes 

 up a great part of the ampullaceous sac of Spongilla, and that of 

 the new granuliferous cells of the colourless Diffiugia pyriformis, 

 assuming that the granuliferous cells are the new brood, and 

 that in both instances, viz. in the amoebous cells of the ampulla- 

 ceous sac and the granuliferous cells of Dijfflugia, respectively, 

 the germs are derived from a granulation of the nucleus. 



Further, should the conjugation of the tests of Difflugia pijri- 

 formis be hereafter shown to be connected with the impregnating 

 process, then it may be fairly assumed that a similar conjugation 

 takes place between two reproductive cells of Bpongilla, which 

 may lead to a granulation of the nucleus there also, and this, 

 again, to the production of the number of amoebous cells which 

 make up the chief bulk of the seed-like body at the commence- 

 ment, and which, after the capsule has been secreted round 

 them, ultimately enlarge and pass into the globular cells which 

 fill the cavity of the seed-like body, and which, lastly, in their turn, 

 on the issue of the sponge-substance, follow the development 

 above mentioned. 



If, then, the refractive "cells" or granules of the globular cells 

 of the seed-like body in Spongilla be the same as the refractive 

 amylaceous granules of Difflugia pyriformis, then in those Amcebce 

 in which I have described them as " ovules," and wherever they 

 occur in the Rhizopoda, the same view must be taken of them, 

 viz. that they pertain to the nature of, if they be not fully deve- 

 loped starch-granules. 



I long since pointed out that Spongilla abounds with starch 

 in all forms. Auerbach has demonstrated it in Amceba bilim- 

 bosa, and I have also shown that it exists in the chambers of the 

 Foraminifera (viz. in Operculina Arabica), and now in Difflugia 

 pyriformis. 



Again, as in Euglena (where I also formerly thought similar 



