238 GENETICS [Bot. Absts., Vol. VI, 



1640. Blaringhem, L. Variations florales chez la Grande Marguerite (Leucanthemum 

 vulgare, Lamarck.) [Floral variation in Leucanthemum vulgare.] Compt. Rend. Acad. Sci. 

 Paris 169: 193-195. 1919. 



1641. Boedijn, K. Die Chromosomen von Oenothera Lamarckiana, mut. simplex. 

 [The chromosomes of Oenothera Lamarckiana mut. simplex.] Zeitschr. indukt. Abstamm. 

 Vererb. 24:71-76. Aug., 1920. 



1642. Bouin, P. Sur la dimegalie des spermies dans certaines doubles spermatogeneses. 

 Sa signification. [On dimegaly of sperms in certain cases of double spermatogenesis. Its 

 significance.] Compt. Rend. Soc. Biol. 83: 432-434. Mar., 1920. — Two sorts of spermatogonia 

 exist in Scolopendra, one with large, one with small chromosomes. Spermatogenesis is same 

 in both except that growth is much greater in those with large chromosomes. Quantity of 

 chromatin is held to cause larger growth. By analogy with another myriapod, large sperms 

 are believed to be female-determining, small ones male-determining. Facts suggest that 

 heterochromosome in forms that have one is merely trophic in function, that its chromatin is 

 not different from that of other chromosomes, and that effect of its presence is due to larger 

 amount of chromatin, not to different kind. — A. Franklin Shull. 



1643. Bouvier, E. L., and d'Emmerez de Charmoy. Mutation d'une Caridine en Ort- 

 mannie et observations generates sur les mutations evolutives de Crevettes d'eau douce de la 

 famille de Atyides. [Mutation of a Caridine into Ortmannia, and general observations on the 

 evolutive mutations of freshwater crustaceans of the family Atyidae.] Compt. Rend. Acad. 

 Sci. Paris 169:317-321. 1919. 



1644. Castle, W. E. Model of the linkage system of eleven second chromosome genes of 

 Drosophila. Proc. Nation. Acad. Sci. [U. S.] 6:73-77. 2 fig. Feb., 1920.— Bridges and 

 Morgan's linkage data of the second chromosome of Drosophila form the basis of another 

 model in three dimensions similar to those which Castle has previously published. It shows 

 the second chromosome genes "lying roughly in a linear chain winding cork-screw fashion 

 through the model." Gowen's data for the third chromosome have been subjected to similar 

 treatment, and although the model is not figured the genes are said to fall "into a curved 

 band lying nearly in one plane" in the manner pointed out by Sturtevant, Bridges, and 

 Morgan for the sex chromosome model. It is now admitted that according to the linear 

 idea, map distances in excess of 50 may occur, though double crossing over prevents them 

 from being recorded, and that map distances do not correspond with crossover percentages 

 except where the crossover values are low. The fact that one model closely approaches the 

 linear, and that the indefinite lengthening of all the longer distances in the other — cutting 

 of all wires over 40 units long— would straighten it out, so as to closely approach a linear 

 system, leads to the following conclusion: "that the model supports the linear hypothesis, if 

 it be supposed that the longer distances have been shortened by double crossing over, and 

 that map distances in such cases should exceed crossover percentages. — H. H. Plough. 



1645. Chodat, R. La panachure et les chimeres dans le genre Funkia. [Variegation and 

 chimeras in the genus Funkia.] Compt. Rend. Soc. Phys. Hist. Nat. Geneve 36: 81-84. 

 1919. — Author studied chimera-like variegation in leaves of three species of Funkia. In 

 F. Sieboldiana he found two contrasting types— variegata albo-marginata with largely white- 

 margined leaves, and variegata medio-variegata with the white portion largely in the center 

 of the leaf. Baur considers several of these variegated types, such as are found in Euonymus 

 and Pelargonium, as periclinal chimeras. Author finds in variegated Funkias that none of 

 the usually colorless sub-epidermis is present above the green regions; hence he questions 

 considering them as periclinal chimeras, but uses this hypothesis in analyzing them. He 

 does not consider Funkia variegations as reversions such as the variegations described by 

 Bateson in Euonymus, because in Funkia the leaves are all of same type on one plant, while 

 both normal and variegated leaves occur on the same plant in case of Bateson's studies. — 

 In monocotyledons of the Funkia type the epidermis is colorless except for the green guard- 



