REACTIONS OF CELL-BODIES AND PSEUDOPODIAL 

 FRAGMENTS OF DIFFLUGIA} 



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

 University of Virginia. 



Introduction. 



The purpose of this paper is to record a number of observations 

 which were prompted by an incident occurring on October 7, 1919, 

 while one of us (Kepner) was watching a Difflugia pyriformis 

 Ehrenberg under the compound microscope. The animal suddenly 

 retracted an unusually long pseudopod, and in doing so its distal 

 end was torn off. In a short time the fragment began to show 

 amoeboid movement ; meanwhile the animal sent out other pseudo- 

 pods, and within a few minutes the two masses of protoplasm made 

 contact and fusion took place. This naturally called to mind the 

 work which had been done by others on regeneration and restitu- 

 tion; therefore a series of experiments were undertaken in order 

 to find out to what extent, if any, this phenomenon was exhibited 

 in Difflugia. 



It is generally known that many animals possess conspicuous 

 powers of regeneration. For example : snails are able to regen- 

 erate tentacles ; earthworms, flatworms, and polyps may have their 

 bodies severed and each fragment be able to restore the parts that 

 it lacks to complete a body. Verworn (1892) observed that sev- 

 ered fragments of Orbitolites would occasionally adhere to the ends 

 of parental pseudopods. Jensen (1896) pointed out that Orbito- 

 lites and Amphistegina (belonging to the order Foramifera) would 

 sometimes recover fragments belonging to themselves and make 

 them again a part of their bodies. Wilson (1907, '11) has shown 

 that the tissues of sponges broken up or macerated by passage 

 through the meshes of bolting cloth, so that the component cells 



1 This is the first of a series of contributions on this subject. More 

 extensive observations and experiments are now being conducted by the junior 

 author with other genera of Rhizopods, as well as with the genus Difi 



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