no 



GARY N. CALKINS 



about the cells. In experiment 60 the cell was cut obliquely 

 through the anterior half. After 4 hours B had divided into a 

 fragment B,' and a normal cell B." After 24 hours A and B" were 

 large and perfect and B' was perfect but of only one-sixth size. 

 D. If cut just prior to separation. Experiments 26A, 26B, 

 27A, 27B, 50 and 65 were on cells almost ready to separate. The 

 nuclear conditions, therefore, were similar to those of the cells 

 described in section A. In no. 26 the dividing cell was first cut 



Fig. 15 Experiment 62. Cell cut during a late phase of division. Each frag- 

 ment subsequently divided in the original plane of division, but none of the four 

 parts regenerated in 48 hours. 



through at the delicate point of attachment (cf. fig. 3A) Cell 

 A was then cut longitudinally through the center. After 2 hours 

 A' had three cirri and a nearly complete adoral zone A" had five 

 cirri and one-half the adoral zone. After 18 hours A' was com- 

 plete and normal, A" had the same 5 cirri and half the adoral 

 zone and failed completely to regenerate. Cell B {2QB) was also 

 cut longitudinally through the center. After 2 hours B' had three 

 cirri and three-fourths of an adoral zone; B" had five cirri and 

 three membranelles. After 18 hours B' was complete and normal 

 but small; B" has not regenerated, and did not regenerate later. 



