WENRICH: spermatogenesis of PHRYNOTETTIX MAGNUS. 125 



D. Summary of Conclusions. 



It is believed that the present study of the spermatogenesis of 

 Phrynotettix magnus has demonstrated : — 



1. That conjugation of the chromosome-pairs is by parasynapsis. 



2. That the majority of the bivalent chromosomes divide equa- 

 tionally in the first maturation division. 



3. That the chromosomes retain their individuality through the 

 spermatogenic cell-generations. 



4. That the so-called ' plasmosomes ' take their origin from some 

 definite region (granule) of particular chromosomes, but that they 

 may be variable in occurrence and in extent of development. 



5. That in the maturation divisions {e. g. chromosome-pair Ci) 

 the law of chance is followed in the distribution of the chromosomes. 



6. That each chromosome possesses a definite organization, which 

 is expressed in the constancy of the relative sizes and positions of its 

 chromomeres (as seen, e. g., in chromosome-pair B). 



In addition, the possibilities are suggested that: — (1) the matter 

 of the behavior of unequal pairs of chromosomes in regard to distribu- 

 tion and recombination may be tested by breeding experiments, (2) 

 the constancy in the arrangement of clu-omomeres along the length 

 of the chromosome-tlu-eads, as described for chromosome-pair B, 

 may have a meaning related to that suggested by Morgan's " hnear- 

 arrangement" hypothesis, and (3) that in the varying types of chromo- 

 some-pair C there may exist a mechanism for the transmission of 

 multiple allelomorphs. 



