DESICCATION IN PHILODINA ROSEOLA. 389 



not think that there is any doubt but that the former supposition 

 is correct. The chromatic material in some form actually does 

 pass into the cytoplasm during the dry period. 



Whatever may actually happen to the chromatin in the way 

 of a change of position it seems certain that the purpose of all 

 the position changes outlined are one, namely to keep the 

 chromatin within a working radius of the material to be oxidized. 

 The oxidations referred to in this connection are the breaking 

 down of complex food materials in the cytoplasm with the con- 

 sequent release of metabolic water during the process. The 

 details of this process are discussed in another paragraph. 



The nucleus of the gregarines is similar in many points of 

 structure with that of the rotifer. Montgomery ('98), speaking 

 of an unnamed gregarine from Carinella annulata says: " Now as 

 the gregarine grows, at the same time both nucleus and the 

 total mass of the nucleolar substance increase in size; but the 

 nucleus cannot grow without the addition of a substance or 

 substances to it which have been derived from without. Ac- 

 cordingly, I suppose that the substance of these granules has an 

 extranuclear origin, a substance, i. e., which having penetrated 

 the nucleus from the cytoplasm, undergoes ,a chemical change 

 in the nucleus and there becomes precipitated in the form of 

 granules, for no such substance occurs in granular form in the 

 cytoplasm. The growth of the nucleoli might then be explained 

 on the assumption of the intussusception of this substance by 

 the nucleoli." It seems probable that the rotifer nucleolus 

 grows at the time of recovery from desiccation in the fashion 

 outlined by Montgomery for the gregarine nucleolus. Drying 

 then, brings about a reversal of this process and the normal 

 condition is resumed only when moisture is restored. 



In considering the movements of chromatin from the nucleus 

 into the cytoplasm one is struck by the similarity between the 

 phenomena here observed and those described by Woodruff 

 and Erdmann in their paper upon periodic reorganization in 

 Paramoecium aurelia. 



These authors working upon W 7 oodruff's non-conjugating line 

 of P. aurelia, found that there was a periodic nuclear reorganiza- 

 tion. "This nuclear reorganization consists of a gradual dis- 



