June, 1920] GENETICS 307 



2091. Bouquet, A. G. 15. Pollination of tomatoes. Oregon Auric Exp. Sta. Bull. 187. 

 29 p., 5 Jig. 1919.- -Author notes fact that when tomatoes are grown under glass unfavorable 

 environmental conditions, such as absence of insects, relation of several reproductive organs 

 in the development of the (lower, and the correlation of the vegetal ive and reproductive sys- 

 tems of the plant, contribute to unfruitful mss which varies from IS to 79 per cent. By liand- 

 pollinations, in which the blossoms were emasculated, and pollen applied artificially, 11 per 

 cent of fruitfulness was obtained. Hand-pollinations also increased the earlinesB of fruiting 

 by 21 days. [See Bot. Absts. 3, Entry 2385.]— C. E. Myers. 



2092. Bhidges, Calvin B. Specific modifiers of eosin eye color in Drosophila melano- 

 gaster. Jour. Exp. Zool. 28: 337-384. July 5, 1919. — Demonstration has been made of eight 

 mutant genes which by themselves produce little or no effect upon eye color of flies homozy- 

 gous for them, yet which modify eye color of sex-linked mutant "eosin." These "specific" 

 and "disproportionate" modifications are clear and simple cases of "multiple genes." Each 

 is the result of coaction of a specific modifying gene (cream a, cream II, dark, whiting, 

 cream III, cream b, pinkish, cream c) and of a particular gene (eosin) which latter is neces- 

 sary as a "base" or "differentiator." The scale of modifications of eosin produced by these 

 several modifiers ranges on the one hand to a deep pink darker than "eosin," and on the other 

 to a pure white. In origin these modifiers were entirely independent of one another, and the 

 order of their occurrence bears only a random relationship to the dark-light seriation. The 

 main significance of the facts presented is in their bearing on the question of method by which 

 selection attains its results. — Calvin B. Bridges. 



2093. Bridges, Calvin B., and Otto L. Mohr. The inheritance of the mutant character 

 "vortex." Genetics 4: 283-306. 1 fig. May, 1919.— The character "vortex," affecting thorax 

 of Drosophila melanogaster, depends primarily on two mutant genes — one in second chromo- 

 some (vortex II) and one in third chromosome (vortex III). Male flies must be homozygous 

 for vortex II and for vortex III to show the character; but a small proportion of such males 

 nevertheless fail to show it. Vortex females must also be homozygous for vortex II and gen- 

 erally for vortex III; but about 20 per cent of females homozygous for vortex II show the char- 

 acter wdien only heterozygous for vortex III. The proportion in which vortex III is domi- 

 nant is increased by a third modifier (probably also in the second chromosome) which acts as 

 a dominant sex-limited intensifier. The factor streak inhibits the appearance of the vortex 

 character; but still another factor, located very near streak in the second chromosome, allows 

 the appearance in streak flies of a vortex of a somewhat altered type. — Alexander Weinstein. 



2094. Bridges, Calvin B. Maroon — are current mutation in Drosophila. Proc. Nation. 

 Acad. Sci. 4: 316-318. Oct., 1918. — The recessive eye-color mutation "maroon" has recurred 

 independently at least four times, a phenomenon since found in several other loci. Located 

 in third chromosome at locus 15.2. Maroon and "pink" are "non-modifiers" of each other, 

 as most pink eye-colors have since been found to be. Third independent mutation to maroon 

 occurred in chromosome already carrying new mutation "dwarf" and a gene with specific 

 effect on crossing-over in third chromosome, probably identical with previous mutation 

 "Cm". In "dichaete" region (including maroon) there is no great difference between homo- 

 zygous and heterozygous Cm conditions. Detailed data will appear in Carnegie Institution 

 Publication 278.— C. R. Plunkett. 



2095. Brotherton, W. E. Note on inheritance in Phaseolus. Ann. Rept. Michigan 

 Acad. Sci. 20 (191S) : 152. 1919.— P. vulgaris (dwarf variety) X P. multijlorus (tall variety) 

 in Fi showed 50 per cent decrease in length of hypocotyl, 100 per cent increase in length of 

 epicotyl compared with P. vulgaris; cotyledons epigeal, plants dwarf. Tschermak found 

 hypogeal cotyledons dominant. Cotyledons epigeal or hypogeal is not important. Genetic 

 factors concern length of hypocotyl. — W. E. Brotherton . 



2096. Burger, Owen F. Sexuality in Cunninghamella. Bot. Gaz. 68: 134-146. Aug., 

 1919. — Author has tabulated the sexual activity of 25 or 26 races of Cunninghamella bcrthol- 

 letiae as shown by the presence or absence of zygospore formation when 5 of these races were 



