32 WM. A. KEPNER AND B. D. REYNOLDS. 



ments were separated by the distance of about fifty micra, and for 

 two minutes they moved around quite actively, but no progress 

 was made toward uniting. They were then placed in contact, by 

 using a glass needle, so that now they were in the positions shown 

 in Fig. 7 — m. This contact was a very close one, the adjoining 

 surfaces being very extensive and the line of demarcation quite 

 indistinct, yet discernible. Ten minutes later the activity of the 

 fragments had begun to cease and they showed signs of rounding 

 up into spherical bodies, each piece into its respective sphere (Fig. 

 7 — n). After ten more minutes the spherical condition had been 

 attained and the pieces showed only a small point of contact (Fig. 



7—o). 



Thus, after having been placed in direct contact, there was a 

 failure on the part of these two fragments of ectoplasm to unite — 

 though they had come from the same cell. It seems, then, from 

 our observations, that enucleated ectoplasms do not fuse with each 

 other. 



VI. Will Difflugia Fuse with Pseudopodial Fragments Be- 

 longing to an Individual of a Different Species? 



(a) As Food, (b) By Protoplasmic Union. 

 The criteria for determining whether or not the fragments serve 

 as food have been set forth in a previous part of this paper. How- 

 ever, since the reaction of an individual toward fragments belong- 

 ing to closely related forms was proposed as one method for 

 determining this, these experiments were designed to shed some 

 light on this subject. Furthermore, it occurred to us that in such 

 organisms an individual might fuse with foreign fragments in the 

 same manner described for cell-bodies and their own fragments. 

 The results obtained were such that it will not be necessary to 

 make a distinction between (a) and (b) in discussing the reac- 

 tions. The method which we employed was to take two Difflugia 

 of different species and place them near each other in a drop of 

 water, and as soon as one of the animals had extruded a long 

 pseudopod it was cut off and the animal then removed from the 

 drop, leaving its fragment and the other individual behind. At- 

 tempts were made in this way to cross the protoplasm of all the 

 various species of Difflugia previously mentioned, viz. : D. acumi- 



