REACTIONS OF CELL-BODIES OF DIFFLUGIA. 25 



separated parts might follow a mucous trail, or even invisible 

 strands of protoplasm, and thus contact would be effected. For 

 this reason, in most cases after a pseudopod was severed the cell- 

 body was moved to a considerable distance, and yet the fragment 

 was recovered. Again the cell-body has been moved in a wide 

 detour around on another side of its fragment, after which it 

 would approach without regard to the course along which it had 

 been pushed. The mouth of the shell has been placed in every 

 angle to the fragment from zero to one hundred and eighty de- 

 grees; nevertheless the fragment is usually recovered. To give 

 the details of each experiment would require too much space and 

 necessitate repetition of similar results; therefore, the following 

 two observations have been selected as typical of the usual re- 

 action : x 



On July 24, 1920, the end of a pseudopod was cut from a 

 Difflugia vulgaris by Mr. E. Paylor, of this laboratory, after which 

 the cell-body was immediately moved 500 micra away from it, the 

 mouth of the shell being directed away from the fragment, as 

 shown in Fig. 1 — A. Within a minute the animal, which had with- 

 drawn into its shell after the operation, began to send out two 

 pseudopods. After these pseudopods had been extended to a dis- 

 tance of about fifty micra, their ends adhered to the glass slide on 

 which the animal was lying. Then by a movement somewhat simi- 

 lar to a hand-spring the body proper was thrown over the extended 

 pseudopods, so that now the mouth of the shell was pointed toward 

 the fragment (Fig. 1 — B). The animal then began to move in 

 the direction of the fragment, moving in a counter-clockwise curve 

 as indicated by Fig. 1 — C, D, E, and F. This movement was con- 

 tinuous until the fragment was encountered and reappropriated 

 through fusion of the two masses of protoplasm (Fig. 1 — G). 



The second example given to illustrate the phenomenon of fusion 

 is perhaps more interesting, for in this case more than one frag- 

 ment was involved. In this experiment exact record of the time 



1 We realize that the conclusions drawn in this paper would be more 

 convincing if we published our data in extenso, but since this is a pre- 

 liminary report of observations on a subject which is now being actively 

 investigated with a view to further and more extensive publications, it 

 seems best to present our results here by means of typical experiments 

 and general statements regarding the entire investigation. 



