BEHAVIOR AND FUNCTIONS OF THE NUCLEUS 285 



nuclear membrane, doubtless facilitating their coalescence into 

 one mass during oral redifferentiation and especially in division. 

 When fully deployed the strand connecting individual nodes may 

 be exceedingly tenuous (Fig. 79), yet rarely do terminal nodes break 

 off and not participate in coalescence during fission. Opinions 

 differ regarding whether separated nodes or sections of the nucleus 

 can rejoin their fellows. Stolte (1922) observed that broken nuclear 

 chains in vacuolated dividers condense separately, and I too have 

 found occasionally a double fusion mass; but he stated categori- 

 cally that permanent reunion was not possible because the nuclei 

 were within separate membranes. This supposed behavior is, 

 however, contrary to common experience with hypotrichs, such 

 as Oxytricha, in which widely separated macronuclei, for which 

 there is no evidence of a common boundary, nevertheless fuse at 

 every division. Much earlier, Prowazek (1904) had reported that 

 transected nuclear chains " regenerated" separately, producing two 

 rows of beads; but whether the nuclear volume was doubled he 

 did not tell us. It is probable that the normal nucleo-cytoplasmic 

 ratio was not upset. 



Weisz (1949a) reported that broken nuclear chains can rejoin. 

 I severed the nuclear strand in coeruleus into five or more pieces 

 and its distribution was then for a while disturbed, but the animals 

 later became normal to all appearances, with the nodes closely 

 approximated in a single uniform row in the usual location 



A 



Fig. 79. Photographs of S. coeruleus showing macronucleus as 



seen (A) in living stentor against dark field and (B) after feulgen 



staining to reveal intemodal connections. 



