DEVELOPMENT OF THE EGG OF CLAVA LEPTOSTVLA. 221 



less flattened. It is at this stage that the first indications of 

 maturation becomes apparent, namely, the shrinking and gradual 

 disappearance of the nuclear membrane. This is particularly 

 well shown in Fig. 2, PI. IX. About the same time, or in some 

 cases slightly before, there is also an evident dissolution of the 

 chromatin network, unaccompanied by any indications of chro- 

 mosomes. In this respect these eggs closely resemble those of 

 Endcndriuin and Pcnnaria. The most painstaking attempts to 

 differentiate these bodies by staining operations have as fre- 

 quently failed. It seems to me we are forced to the conclusion 

 that the appearance of dissolution is indeed a fact, and that at 

 this stage there is a general dissipation of chromatin, and per- 

 haps other nuclear matter, into the cytoplasm. 



Behavior of the Nucleolus. Usually at about this stage marked 

 changes take place in the nucleolus. In several instances it has 



o i 



been found to migrate bodily from the germinal vesicle into the 

 cytoplasm where it is gradually dissipated and probably assimi- 

 lated. At this point I find my observations closely in accord 

 with those of Harm (op. cit., p. 24). " Wahrend also hier der 

 Nucleolus in toto vor der Polkorperchenbildung aus dem Keim- 

 blaschen heraustritt, urn vom Eidotter aufgenommen und resor- 

 birt ZLI werden, verbleibt er in anderen Fallen in demselben und 

 zerfallt dort in mehrere Kugelchen." 



Just prior to this migration of the nucleolus into the cyto- 

 plasm it was found to show varying degrees of vacuolation, in ad- 

 vanced stages of which it was often seen to partially shrink and 

 collapse, as if there had been a loss of nucleolar substance. 

 Something of this may be observed in several of the photographs 

 already referred to. 



Conditions very similar to these I have elsewhere described in 

 connection with other hydroid eggs (op. cit., O4 4 , p. 562). Mont- 

 gomery has cited many similar features which had come under 

 his own observations, as well as observations of a like character 

 made by many others. Those who are particularly concerned 

 will find his discussion exceedingly interesting and suggestive, as 

 well as including a valuable summary of evidence bearing on this 

 problem. I may say, however, in passing that I have failed to 

 find any indications in the present case of the metamorphosis of 



