236 Chas. W. and G. T. Hargitt. 



somal vesicles in the telophase of the first division and believes that 

 they represent the gonomeres of Hacker (1902), i. e., paternal and 

 maternal nuclear constituents which have remained distinct and 

 separate. Such a view is attractive, but the conditions in coe- 

 lenterates other than Linerges seem not to bear out this interpre- 

 tation. In Cyanea the presence of more than two vesicles, and of 

 vesicles of unequal size, is rather opposed to this view. We are 

 more strongly opposed to this suggested interpretation, because of 

 facts presented in another paper (G. T. Hargitt, 1909) that some of 

 the Hydromedusse are even less regular and constant in this 

 feature. For example in Tubularia crocea it was found that in the 

 cleavage stages, up to what represents a blastula, such double nu- 

 clei, and indeed any chromosomal vesicles, were absent, while 

 in the cells of the blastula and in the developing ectoderm and en- 

 toderm cells double nuclei were common. Thus in the earlier 

 stages where the distinctness of sperm and egg chromosomes should 

 have been more evident there was a total absence of this condition 

 in Tubularia. As is well known also, Dublin (1905) found that 

 nuclei in Pedicellina which appeared double in somatic and germ 

 cells were not to be considered as representing gonomeres. These 

 several points appear to offer an objection which it is difficult to 

 overcome. Since in many animals there are often formed many 

 chromosomal vesicles in the telophase of division and these later 

 unite into a single vesicle, w^hy may not these vesicles wherever 

 found be better considered as simply stages in the reorganiza- 

 tion of the nucleus, sometimes passed through and sometimes not, 

 at least until it can be demonstrated in each case that the pater- 

 nal and maternal nuclear constituents do actually remain distinct 

 and separate. In Cyanea, Aurelia and certain Hydromedusse at 

 least there seems to be no question of the absence of any evidence 

 of gonomery. Chromosomal vesicles often form, and may delay 

 a long time before uniting into a single vesicle or may even fail to 

 so unite — perhaps as a result of rapidly succeeding division — but 

 there is no evidence in this to warrant the assumption of the dis- 

 tinctness of paternal and maternal constituents. 



