46 WILLIAM E. HOY. 



divided to one'pole so that one half the number of the spermatids 

 receive eleven, the other half, ten chromosomes. Each spermatid 

 also receives one m -chromosome. 



In the oogonial group there are twenty-two chromosomes, 

 which can be arranged in eleven pairs. Of these, four are macro- 

 and two are microchromosomes. Wilson was able to count the 

 chromosomes in the ovarian follicle-cells. These were found to 

 be identical in number with the chromosomes in the oogonia. 

 He says, however, that "not infrequently the number of chro- 

 mosomes is much greater, and the same is true of the nuclei of 

 the investing cells of the ovary, of the oviduct and the fat-body. 

 In the male similar multiple groups are not uncommon in the 

 interstitial and investing cells of the testis. Only in a single 

 case have I succeeded in gaining a clear and complete view of 

 such a group ; but this one case suffices to give, with a great degree 

 of probability, the explanation of the increased number of chro- 

 mosomes. In this case every chromosome is exactly twice the 

 oogonial number, namely 44." This figure, which he gives, is 

 from a cell toward the periphery of a larval ovary, and shows 

 eight macro- and four microchromosomes, twice the number of 

 these particular chromosomes found in the oogonia. He suggests 

 that the chromosomes have divided once without a corresponding 

 division of the cell-body, and he thinks it probable that an 

 increase in number of chromosomes in these particular cells is 

 always due to a process of this kind. 



Wilson also states that although he was unable to obtain 

 perfect preparations of mitoses in other tissues, he is able to 

 assert that in the ectodermal cells of the larva the number of 

 chromosomes is "approximately the same as in the oogonia," 

 and that nowhere else than in the described cases did he obtain 

 a doubling of the number. He concludes that this multiplicity 

 is due, perhaps, either to the fact that the cells in question are 

 degenerating, or that they are highly specialized. 



In 1910, Morrill published his observations on the chromosomes 

 in the oogenesis, fertilization, and cleavage of certain Coreid 

 Hemiptera, among them Anasa. He found that the oogonial 

 groups in Anasa contain twenty-two chromosomes, including four 

 macro- and two microchromosomes. The reduced number in 



