No. 1, August, 19201 GENETICS '' : > 



464. Stibvb, H. Uber experimentell, durch veranderte aussere Bedingungen bervor- 

 gerufene Riickbildungsvorgange am Eierstock des Haushuhnes (Gallus domesticus). [On de- 

 generative processes in tbe ovary of domestic fowl produced experimentally by changed external 

 conditions.] Arch. Entwicklungsmech. Organ. 44: 530-588. Wfuj. L918.- Layingfowls 

 were removed from their normal quarters and placed in close confinement. Aft( ious 

 intervals the birds were killed and the ovaries examined.. In all cases egg production ceased. 

 If the birds were well fed, production was not resumed. The large ova were not resorbed for 

 several months, though degenerative changes took place in the nucleus, which extended to 

 smaller and smaller ova, the longer the birds were kept. If, however, the birds were starved 

 or kept on limited diet for a time, and then fed suitably, the large ova were quickly resorbed, 

 the degenerative changes did not extend to the small ova, and production was resumed after 

 a comparatively brief interval. — //. D. Goodalc. 



465. Stout, A. B. Further experimental studies on self-incompatibility in hermaphrodite 

 plants. Jour. Genetics 9: 85-129. PI. 3-4. Jan., 1920. — Two self-sterile plants of Verbascum 

 phoeniceum were crossed. In F 1( 58 plants were self-sterile, 9 bore some seeds, and 2 were 

 highly self-fertile. From a highly self-fertile plant of this species there were raised (in addi- 

 tion to 27 plants with contabescent anthers) 5 self-sterile plants, 2 plants with some seeds, 

 and 5 highly self-fertile plants. — Sowings made from open-fertilized or commercial seeds of 

 Eschschollzia californica, Nicotiana Forgetiana, Brassica pekinensis, and Raphanus sativus, 

 showed a majority of self-sterile, and a minority bearing few or many seeds. The descendants 

 of each of two self-fertile plants of Nicotiana Forgetiana showed a majority of more or less 

 self-fertile plants. — In Cichorium intybus, 10 plants were uniform as to self-fertility or self- 

 sterility throughout the blooming period. Of the descendants of 3 self-fertile plants, 244 were 

 self-sterile, and 107 bore some seeds. . In the next selfed generation, 205 plants were self- 

 sterile, and 266 self-fertile in various degrees. — It is concluded that self-sterility in some spe- 

 cies is highly variable. — John Belling. 



466. Sto-rtevant, A. H. Contributions to the genetics of Drosophila rnelanogaster. III. 

 Inherited linkage variations in the second chromosome. Carnegie Inst. Washington Publ. 278: 

 305-341. Washington, D. C. 1919.— The data presented demonstrate two genes in second 

 chromosome of Drosophila rnelanogaster, each of which, in females heterozygous for it, greatly 

 decreases crossing-over in region in which it lies. Both genes were found in same female, in 

 stock from Nova Scotia. C u i, located to left of black, makes star black=0, and black purple 

 very small. C U r, located between purple and plexus, greatly reduces purple speck region. 

 Homozygous Cu shows no effect on crossing-over; homozygous C'ni not tested. No crossing- 

 over in males, as always. — Cm, located in right end of third chromosome, greatly decreases 

 cro3sing-over between spineless and rough when heterozygous, but increases it when homozy- 

 gous. Cni.ii, in third chromosome, when heterozygous decreases crossing-over in third chro- 

 mosome, but increases purple curved region of second. — Mechanism of these effects is still unr 

 known. Qther linkage variations are caused by sex, age, temperature, and genetic factors. 

 In all cases, linear order of genes is unchanged, and flies of same constitution, under like 

 conditions, give consistent results. The methods and results are striking confirmation of 

 chromosome view of heredity. — C. R. Plunkett. 



467. Sturtevant, A. H. A new species closely resembling Drosophila rnelanogaster. 

 Psyche 26: 153-155. 1 fig. Dec, 1919.— Describes Drosophila simulans, new species that has 

 hitherto been confused with D. rnelanogaster. New form is common and widely distributed. 

 Specimens can be separated easily only by means of male genitalia. Female rnelanogaster X 

 male simulans produces only daughters, unless the mother carries a Y-chromosome. The 

 hybrids are all sterile. — A. H. Sturtevant. 



468. Sturtivant, Grace. Registration of new varieties. Gard. Chron. 67: 73. Feb. 

 14, 1920.— Plant patents seem impossible in the United States; but the registration of new 

 varieties is important. It is suggested that higher awards should be given for plants in gar- 



