330 GENETICS [Bot. Absts. 



further breeding. The methods and investigations here described may have a practical 

 application, so that the book has special value for plant and animal breeders, as well as for 

 the geneticist. [From publisher's announcement, Zeitschr. Bot. 11: cover page 4. 1919.] — 

 Geo. H. Shull. 



2191. Schmidt, Johs. Racial studies in fishes. II. Experimental investigations with 

 Lebistes reticulatus (Peters) Regan. Jour. Genetics 8: 147-153. 1 graph. June, 1919. — The 

 author is working on the question whether, or to what extent, quantitative racial characters 

 are hereditary. The tropical-American Cyprinodont Lebistes reticulatus (Peters) Regan, a 

 little aquarium fish, was used because it breeds rapidly, and the young possess at birth the 

 full number of vertebrae, dorsal rays, etc. The experiments fall into two groups. In the first, 

 the temperature of the water was varied for one pair of parents from one period of pregnancy 

 to the other and the number of rays in the various broods counted. The results show that 

 the different broods do exhibit a difference in the number of dorsal fin rays, and the number 

 of rays was greater where the young had been developed at a high temperature than where 

 their development took place at a lower temperature. In the second, different pairs of 

 parents were kept in the same environment, the same water. One set of parents both had 6 

 rays and in the other set both had 8 rays. The tables show that the average number of rays 

 approximates that of the parents, respectively, and is therefore genotypical in nature. The 

 author concludes that a fish "race" is largely a statistical conception, implying a mixture of 

 genotypes, with the environment acting only secondarily. — R. K. Nabours. 



2192. Schmidt, J. Investigations on hops (Humulus lupulus). XI. Can different clones 

 be characterized by the number of marginal teeth in the leaves? Compt. Rend. Lab. Carlsberg 

 14: 1-23. 8 fig. 1918. — A statistical study was made of difference in number of marginal 

 teeth on terminal lobes of leaves borne on secondary axes to determine whether the varia- 

 tions were an expression of genotypic differences or were merely phenotypic. The leaves 

 studied were obtained from plants of the same clone observed through three different years, 

 plants from the same clone grown under different external conditions in the same year, plants 

 from different clones, and from hybrid plants the parents of which showed great divergence 

 in respect to the character under consideration. Author concludes that although the number 

 of teeth in the margin of leaves of the hop plant is largely affected by environment, neverthe- 

 less there are differences between clones in respect to the number of leaf-teeth, which are 

 independent of external conditions. — W. W. Stockberger . 



2193. Seiler, J. [Rev. of: Doncaster, L. Chromosomes, heredity and sex: A review of 

 the present state of the evidence with regard to the material basis of hereditary transmission 

 and sex-determination. Quart. Jour. Microsc. Sci. 59:4S7-521. 1914.] Arch. Zellforsch. 

 15:141-143. 1919. 



2194. Seiler, J. Chromosomenstudien an Mischlingen. [Chromosome studies on hy- 

 brids.] [Rev. of: Federley, Harry. (1) Die Chromosomenconjugation bei der Gameto- 

 genese von Smerinthus populi var. austanti X populi. Ein Beitrag zur Frage der Chromo- 

 somenindividualitat und der Gametenreinheit. (Chromosome conjugation in the gametogene- 

 sis of Smerinthus populi var. austanti X populi. A contribution to the individuality of the 

 chromosomes and purity of the gametes.) Ofversigt Finska Yotcnsk. Soc. Forhandl. 57: 

 1-36. 1914-1915. — (2) Idem. Die Spermatogenese des Bastards Dicranura erminea 9 X D. 

 vinula d". (Spermatogenesis of the hybrid Dicranura erminea 9 X D. vinula <?). Ibid. 

 57: 1 20. 1914-1915. — (3) Idem. Die Spermatogenese des Bastards Chaerocampa porcellus 

 9 Xelpenorc?. (Spermatogenesis of the hybrid Chaerocampa porcellus 9 X elpenor d"). 

 Ibid. 58: 1-17. 1915-1916.] Arch. Zellforsch. 15: 137-139. 1919. 



2195. Seiler, J. [Rev. of: IIaask-Bkssell, Gertraud. Digitalisstudien I. (Digitalis 

 studies I.) Zeitschr. indukt. Abstamm. Vererb. 16:293-314. 1916.] Arch. Zellforsch. 15: 

 143. 1919. 



