MOEPHOLOGY AND PHYSIOLOGY OF GENUS URONYCHIA 363 



Thus the process of regeneration delayed the division rate. The 

 only exceptions to this were those cells which were cut during 

 division. In these cells division was completed before the 

 regeneration of the missing parts and resulted in the formation 

 of one normal cell and one which was abnormal in structure 

 because of the cut. The normal cell divided again at the usual 

 rate, while in the operated one division was delayed by the proc- 

 ess of regeneration. 



Obl B 



OblA 



OblC 



OhlD 



ObLE 



Trdns.D 



Text fig. B Diagram showing the planes of cutting as listed in the tables 

 following. 



In order to describe the experiments it is necessary first to 

 describe the way in which cells regenerate. The first evidence 

 of recovery after cutting is the closing over of the cut surface. 

 This is accomplished to some extent by the drawing in of the 

 edges of the body much as Holmes describes for Loxophyllum 

 ('07). However, in Uronychia the cuirass or pellicle is so rigid 

 that this process is not very extensive. Apparently a membrane 

 is formed to cover the rest of the surface. During this process 

 there seems to be a tendency for the body to assume normal pro- 

 portions, but probably the drawing in of the cut surface is enough 



