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



next sought to determine whether or not one individual would 

 fuse with a pseudopodial fragment from another individual of the 

 same species. In order to make conditions similar to those under 

 which organisms have been repeatedly observed to pick up their 

 own fragments, a portion of the protoplasm was removed from the 

 animal concerned before placing a fragment from another indi- 

 vidual near it. The following reaction is an example of what 

 commonly happens when dealing with wild cultures : 



Two specimens of D. spiralis {A and B) were placed in the 

 same drop of water, and a fragment was cut from animal A at 

 10:24 A.M., July 14, 1921. This fragment was carried out of 

 the water as it clung to the glass filament with which the cutting 

 was done. Animal B was now dragged up to the position shown 

 in drawing (Fig. 8). At 10:29 A.M. fragment c was cut from 

 animal B without disturbing the position of either cell ; the opera- 

 tion did not even cause animal A to withdraw its large pseudopod. 

 Specimen B was immediately carried from the drop. Animal A 

 turned away from the fragment to position A' and moved off, but 

 a little later it was moved back to less than half its shell's length 

 from the fragment, only to move away again. For the third time 

 animal A was placed near the fragment of foreign ectoplasm, and 

 though one of animal A's pseudopods passed directly over it, there 

 was no reaction either on the part of animal A or the fragment 

 from animal B. 



Other reactions have been observed in which individuals did 

 fuse with fragments from animals of the same species. However, 

 in all reactions of this sort the organisms were obtained from the 

 same culture. There are two possible explanations for this : (a) 

 The individuals were closely related by having a recent common 

 ancestor, (b) By living in the same surroundings, the environ- 

 mental influences have acted upon both organisms in such a way 

 as to cause an identical physiological state. This is left as an open 

 question, upon which further work is being done. 



Discussion. 

 Verworn (1892) cut off pseudopods from Orbitolites and ob- 

 served that after the severed masses had rounded up into little 

 droplets they would adhere to the ends of pseudopods extended by 



