410 



S. J. Holmes 



free swimming infusoria is more simple than that of the creeping 

 or the permanently attached forms. 



REGENERATION 



While studying the behavior of pieces of Loxophyllum I found 

 that regenerative changes set in soon after the animal was cut in 

 two. A good opportunity was thus afforded for watching the 

 regeneration of the animal which takes place so rapidly that one 

 might almost be said to actually see it going on. To determine, 

 so far as possible, the exact method followed in regeneration is 

 always a matter of interest and importance; and a form in which 



Fig. I Showing the course of regeneration of a piece from the posterior end of Loxophyllum. 

 The dotted line in this and the following figures indicates where the cut was made. 



the process can be watched under the microscope and followed 

 step by step is especially favorable for this purpose. 



A Loxophyllum was cut in two near the middle by a slightly 

 oblique cut (Fig. i). In the anterior piece the sides near the 

 cut end were drawn inward and soon met, thus closing in the cut 

 portion of the margin and giving the piece much the appearance, 

 except in its relatively greater width, of the normal animal. In 

 the posterior piece to which attention was mainly directed, since 

 much greater modifications wxre necessary to restore the normal 

 form, the first step in the process of regeneration was the closing 

 in of the sides at the anterior end. The piece continued to swim 

 forward and backward, undergoing the regular changes in form 



