THE DIPLOID CHROMOSOME COMPLEXES OF THE PIG 191 



cell, which may be considered as the anlage of the future germ 

 cells, retains the two chromosomes intact, while the chromosomes 

 of the cells forming the body tissues break up into as many as 

 sixty fragments. This fragmentation is said to be accompanied 

 by a chromatin diminution. If this be true, the quantity of 

 the chromatin in the cells of the soma is probably not the same 

 as it is in the germ line, contrary to what I have fouijd in the 

 pig and in Oenothers scintillans. A metrical study of the 

 chromosome behavior in Ascaris would be of considerable value. 

 Nachtsheim ('13) found 32 diploid chromosomes in the bee, 

 while Petrunkewitsch ('13) found 64 in the blastoderm of fer- 

 tilized eggs. Hoy ('16) points out that "though the reports of 

 several investigators tend to show that the number of chromo- 

 somes varies in the bee, the number is always 8 or a multiple of 

 this." (Nachtsheim found that the number in the oogonia 

 was 16 and in the oocytes 8. He considers that oogonial chro- 

 mosomes are double, thus accounting for the 32 chromosomes 

 found in the soma.) This condition is from one point of view, 

 comparable to that found by Dr. Caroline Holt ('17) in the cells 

 of the cast off intestinal epithelium of the mosquito, where the 

 number varied from 6 to 72, always in multiples of three. These 

 are degenerating and consequently pathological cells, and differ 

 in this respect from the normal cells of the bee. 



In the Hymenopter, Nematus ribesii, Doncaster ('07) found the 

 diploid and the haploid chromosome number to be 8 and 4 re- 

 spectively, while he counted 16 chromosomes in the ovarian 

 sheath. He considers that the chromosomes of the germ cells 

 may be compound and consist of a number of smaller units 

 which become separated in the somatic cells. 



I am glad to have this opportunity of correcting two regret- 

 able errors that were accidentally inserted in my paper on C'ulex 

 pipiens ('17) in regard to Seller's work on Phragmatobia ('14). 

 In one place I coupled his name with Taylor's as having worked 

 on the mosquito, when the other name should have been Loh- 

 man, and, in referring to his work on the moth, said that he 

 found the somatic chromosome number to be the same as the 

 diploid number of the germ cells. The diploid number is 56 



