GERM CELLS OF COELENTERATES 89 



therefore, as to the correctness of their interpretation on this 

 point. 



In Clava, as well as in Campanularia, another point of some 

 theoretical interest and importance calls for comment. This is 

 in regard to the method of reduction of chromosomes. Beck- 

 with ('09) has shown in Clava, as I have in Campanularia ('13), 

 that when the first maturation spindle forms, the chromosomes 

 are present in the reduced number. This is the usual condition 

 in oogenesis, of course, but as a rule there is a period of contrac- 

 tion of the chromatin into a mass at one side of the nucleus 

 (synizesis) at which time it is supposed that the chromosomes 

 unite in pairs (synapsis). In Campanularia it was found, and 

 figures 1 to 4 here show for Clava, there is no synizesis stage. 

 The only stage which would suggest synapsis is that in which the 

 chromatin is arranged in loops (figs. 1 and 2) and these loops at 

 the time of the first recognizable appearance of the egg cells are 

 already apparently present in the reduced number. This may 

 mean that synapsis does not occur (that is chromosomes do not 

 conjugate) but the chromatin at the time of formation of the 

 chromosomes condenses into half the usual number of bodies. 

 This would indicate a variation in method only and not a differ- 

 ence in effect. But if confirmed it would present evidence 

 against the view of the presence and independence of distinct 

 paternal and maternal chromosomal constituents in each cell. 



Synapsis is assumed to represent a fusion of similar chromo- 

 somes and in many cases the chromosomes which unite are alike 

 in size and shape, and later these separate. If one half the usual 

 number of bodies are produced in the nucleus, but without the 

 preliminary formation of definite chromosomes, to harmonize 

 this with the prevailing view of the fusion of homologous pater- 

 nal and maternal constituents would involve the further assump- 

 tion of a fusion of similar chromatin granules. These would 

 have to be considered as genetically related to granules which 

 entered the cleavage nucleus from the egg and sperm chromatin. 

 While such an interpretation has been theoretically made to 

 explain certain cases of inheritance, as far as I am aware no one 

 has observed any differences in chromatin granules which would 



