192 GENETICS [Bot. Absts., Vol. V, 



1461. Bonne vie, Kristine. Polydaktyli i norske bygdeslegter. [Polydactyly in Nor- 

 wegian peasantry.] Norsk. Mag. f. Lagev. 6: 1-32. 1919. — In several families from different 

 parts of Norway one and the same type of hereditary Polydactyly occurs — a postaxial, asym- 

 metrical Polydactyly, mostly developed on the right side of the body. The extra finger (or 

 toe) was always fixed at the base of the fifth finger, the metacarpalia showing no abnormalities. 

 In all families the character in its occurrence follows the dominant type of inheritance, occur- 

 ring in each of a series (2-5) of generations and in a relatively large number of individuals. 

 The degree of development of the sixth finger (or toe) and its occurrence on one or both hands 

 or feet, however, show considerable variation within each generation, from a well developed 

 finger with three normal phalanges, down to a small soft knob at the side of the hand. — A 

 genealogical investigation proved all the families in question to descend from one and the same 

 parish of Norway and also to have at least one ancestor in common. — Kristine Bonnevie. 



1462. Bonnevie, Kristine. Om tvillingsfodslers arvelighet. Undersokelse over en norsk 

 bygdeslegt. [On the inheritance of twin births. Investigations on Norwegian peasantry.] 

 Norsk. Mag. f. Lagev. 8: 1-22. 1919. — Hereditary disposition of twin births is stated within 

 certain branches of a large country family (counting about 5000 individuals), the multiple 

 births making in these branches no less than 7.7 per cent of all births, while the percentage of 

 twin births within the whole country makes only 1.3-1.4 per cent. Through the "difference 

 method" of Weinberg (subtraction of all twin "pairs" from the number of one-sexed twins) 

 it is proved that about 80 per cent of all multiple births investigated should be considered as 

 two-egged twin births, while probably only 20 per cent of multiple births have been from 

 one egg. Younger mothers (below 30 years old) seem to give rise to one-egg and two-egg 

 twin births in about equal number, while the number of one-egg twin births rapidly decreases 

 among older mothers. The inheritance of two-egg twin births which must depend upon some 

 hereditary character of the ovary is investigated through a genealogical study of the an- 

 cestry of twin mothers. Among 88 twin mothers 73 are shown to belong to twin-producing 

 branches of the families investigated, while the ascendence of 15 twin-producing mothers 

 is unknown. 67 twinning mothers whose ascendence is known through several generations on 

 one (30 cases) or on both sides (37 cases) are without exception shown to descend from twin- 

 producing families through both parents, or through the one of them whose ascendence is 

 known. The type of inheritance seems, therefore, to be that of a recessive character demand- 

 ing for its manifestation that the twinning mother should receive her disposition in a double 

 dose, through both her parents. The investigations are being continued on other families 

 and all results should as yet be considered as preliminary. — Kristine Bonnevie. 



1463. Boulenger, G. A. Un cas interessant de dimorphisme sexuel chez un serpent 

 africain (Bothrolycus ater Giinther). [An interesting case of sexual dimorphism in an African 

 snake.) Compt. Rend. Acad. Sci. Paris 168: 666-669. 1919. — -Sexes are distinguished by 

 number of rows of scales, 19 in female, 17 in male. Variations in other species mentioned in 

 literature are not related or are only indefinitely related to sex. — A. Franklin Shull. 



1464. Burch, D. S. Heredity and economical production of food. Jour. Heredity 11: 

 7-11. 2 fig. Jan., 1920. 



1465. Burt, B. C, and N. Haider. Cawnpore-American cotton: An account of experi- 

 ments in its improvement by pure line selection and of field trials. 1913-1917. Agric. Res. Inst. 

 Pusa Bull. 88. 32 p., 10 pi., 1 fig. 1919. — Describes effort to isolate pure lines adapted to 

 Indian conditions from a badly mixed stock of an American upland variety. — T. H. Kearney. 



1466. Call, L. E. Director's report. Kansas Agric. Exp. Sta. 1917-18. 63 p. 1918.— 

 Author states breeding parthenogenetic Appotettix indicates certain characters may be af- 

 fected by temperature and moisture. Of several thousand parthenogenetic offspring, all 

 were females except four. Parthenogenesis occurs among homozygotes and heterozygotes. 

 "Crossing over" and "linkage" also occur. — Corn leaf aphis: Aphis maidis, reared at tempera-, 

 ture of 84° to 90°F. produced no winged forms; reared at 72°F. one winged form appeared 



