280 GENETICS [Box. Absts., Vol. VIII, 



that of many mammals in which the female cells undergo early stages of maturation before 

 birth, while those of males delay until near sexual maturity. Author observes that both 

 male and female tadpoles undergo early maturation stages simultaneously. Cells of male 

 undergo 2 cycles: First cycle during 1st year reaches 1st maturation division and aborts; 

 2nd cycle during 2nd year produces mature sperm just before metamorphosis. Pachytene 

 cells of female tadpole enter growth stage and become typical oocytes. So-called "oocytes" 

 in male tadpole and newly metamorphosed frog arise during growth stage but later degenerate. 

 Presence of yolk-bearing cells is not a good sex criterion since male cells of Ascaris and the 

 Prosobranchs form yolk. Author suggests that "oocytes" are of same nature as cells of 

 Bidder's organ, that due to precocious sexual cycle some germ-cells not able to complete 

 their cycle grow to an abnormal size and appear as oocytes. — C. L. Parmenter. 



1947. Thompson, David H. A new type of sex-linked lethal in Drosophila. [Abstract.] 

 Anat. Rec. 20 : 215. 1921 . — A new sex-linked recessive factor has appeared which kills females 

 in double dose and can be recognized in the males which it does not kill. In these males it 

 affects the mesothorax since the wings are held erect and the 2nd pair of legs is feeble. Crosses 

 between heterozygous females and erect males give a sex ratio of 1 female to 2 males while 

 other lethals give ratios of 2 females to 1 male. Linkage experiments indicate a locus of 

 about 38 in the sex chromosomes. The lethal effect and the character "erect" are manifes- 

 tations of the same factor as indicated by the absence of crossing over between the two. This 

 erect lethal kills females homozygous for it while other sex-linked lethals kill males. The 

 possibility is offered of producing balanced lethals in the sex chromosomes. Recently a 

 dominant accessory factor has appeared which makes erect dominant in the heterozygous 

 females. — David H. Thompson. 



1948. Thomson, J. Arthur. [French rev. of: Castle, W. E. Studies of heredity in 

 rabbits, rats and mice. Carnegie Inst. Washington Publ. 288. 56 p., 3 pi. 1919.] Scientia 

 29: 142-144. 1921. 



1949. Thomson, J Arthur. [French rev. of: Morgan, T. H., and others. Contri- 

 butions to the genetics of Drosophila melanogaster. Carnegie Inst. Washington Publ. 279. 

 388 p., 12 pi., 105 fig. 1919.] Scientia 29: 144-145. 1921. 



1950. TiscHLER, G. [German rev. of: Ostenfeld, C. H. Eamdannelse uden befrugtn- 

 ing og Bastarddannelse hos nogle Kurvblomstrede samt disse ForholdsBetydningforformernes 

 constans. (Studies on fertilization and hybridization in Compositae and their significance 

 for the production of constant forms.) K. Vet. og Landbohjiskole Aarskr. 1919: 207-219. 1 

 fig. 1919.) Zeitschr. Indukt. Abstamm.- u. Vererb. 25: 176. 1921. 



1951. Weinstein, Alexander. Homologous genes and linear linkage in Drosophila 

 virillis. Proc. Nation. Acad. Sci. 6: 625-639. 2 fig. Nov., 1920.— Author describes "cross- 

 veinless," a sex-linked mutant character in Drosophila virilis which constitutes a 3rd possible 

 parallel to sex-linked characters in Drosophila melanogaster. Data are given on linkage of 

 factors for crossveinless and hairy with other factors; also evidence of linear linkage as op- 

 posed to 3-dimensional linkage in this species. Data are presented on coincidence, indicating 

 that coincidence resembles that in X chromosome of D. melanogaster. Author discusses 

 question of "homology of apparently similar factors" and answers the question "are genes 

 with similar somatic effects chemically similar?" in the negative. — C. W. Metz. 



1952. Wellington, R. Recent investigational work with the tomato. Trans. Peninsula 

 Hort. Soc. [Delaware] 9: 73-76. 1920.— Author notes that Fi seed usually gives a greater 

 yield than either parent and produces a uniform product. An objection is that crossed seed 

 must be used each season. Method of producing crossed seed is given. — Work of previous 

 investigators is reviewed, all of whom obtained increased yields in Fi over the parent vari- 

 eties.— In experiments conducted at Minnesota, 1911-1918, the average increase was nearly 

 4 pounds per plant, including green and ripe fruit, but not all crosses were equally productive, 



