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



1756. Siemens. [German rev. of: Gasstjl, R. Eine durch Generationen pravalierende 

 symmetrische Fingerkontratur. (A symmetrical contraction of the fingers prevailing through 

 generations.) Deutsch. med. Wochenschr. 44:1197-1198. 2 fig. 1918. [See Bot. Absts. 5, 

 Entry 367.] Idem. Nachtrag zu meiner Mitteilung iiber "Eine durch Generationen prava- 

 lierende symmetrische Fingerkontratur." (Supplement to my contribution on a symmetrical 

 contraction of the fingers prevailing through generations.) Deutsch. med. Wochenschr. 44: 

 1450. 1918.] Zeitschr. indukt. Abstamm. Vererb. 24: 103-104. Aug., 1920. 



1757. Siemens. [German rev. of: Zweig, Ludwig. Uber einen Fall von Epidermolysis 

 bullosa hereditaria. (On a case of epidermolysis bullosa .hereditaria.) Arch. Dermatologie 

 u. Syphilis 120: 1-6. 19.] Zeitschr. indukt. Abstamm. Vererb. 24: 104. Aug., 1920. 



1758. Sirks, M. J. Hereditas, genetiskt arkiv utgivet av mendelska sallskapet i Lund. 

 (Hereditas, genetic archive published by the Mendelian Society of Lund.) Vol. 1, Haft 1. 

 Berlingska Boktryckeriet: Lund, 1920.] Genetica 2:373. July, 1920. — Notice and review 

 of the first number of new Swedish genetical journal, Hereditas. — G. H. Shull. 



1759. Sirks, M. J. Prae-Mendelistische erfelijkheidstheorieen. [Pre-Mendelian theo- 

 ries of heredity.] Genetica 2 : 323-346. 3 fig. July, 1920. 



1760. Sirks, M. J. [Dutch rev. of: Akerman, A. Speltlike bud-sports in common 

 wheat. Hereditas 1:116-127. 6 fig. 1920.] Genetica 2:365-366. July, 1920. [See Bot. 

 Absts. 6, Entry 1565.] 



1761. Sirks, M. J. [Dutch rev. of: East, Edward M., and Donald F. Jones. In- 

 breeding and outbreeding. 14 X 21 cm., 285 p., J+6 fig. J. B. Lippincott: Philadelphia, 1919. 

 (See Bot. Absts. 4, Entry 571; 5, Entries 337, 1495 and 1607.)] Genetica 2: 370-373. July, 

 1920. 



1762. Sirks, M. J. [Dutch rev. of: Heribert-Nilsson, N. Zuwachsgeschwindigkeit der 

 pollenschlauche und gestorte Mendelzahlen bei Oenothera Lamarckiana. (Decline in pollen- 

 tube growth and deranged Mendelian ratios in Oenothera Lamarckiana.) Hereditas 1: 41-67. 

 1 fig. 1920.] Genetica 2:375-377. July, 1920. 



1763. Sirks, M. J. [Dutch rev. of: Rasmtjson, Hans. Uber einige genetische versuche 

 mit Papaver Rhoeas und Papaver laevigatum. (Some genetical experiments with Papaver 

 rhoeas and Papaver laevigatum.) Hereditas 1: 107-114. 1920.] Genetics 2:377-378. July, 

 1920. 



1764. Sirks, M. J. [Dutch rev. of: Tedin, Hans. The inheritance of flower colour in 

 Pisum. Hereditas 1 : 68-97. 1 pi, 2 fig. 1920.] Genetica 2: 378-379. July, 1920. 



1765. Smith, Bertram G. The individuality of the germ-nuclei during the cleavage of the 

 egg of Cryptobranchus allegheniensis. Anat. Rec. 17: 323. Jan., 1920. — Author's abstract 

 of paper read before American Society of Zoologists, St. Louis, December 30, 1919. — In the 

 fertilization of the egg of Cryptobranchus allegheniensis the germ-nuclei do not fuse, and in 

 the first cleavage mitosis each gives rise to a separate group of chromosomes, whose descend- 

 ants pass separately to the daughter-nuclei. During the ensuing resting stage each germ- 

 nucleus is represented by a structurally distinct vesicle. The separateness of the germ- 

 nuclei is thus maintained throughout the entire nuclear cycle. Throughout early cleavage 

 the nuclear divisions are of the same duplex type, and the resting nuclei are always dis- 

 tinctly double. The genetic continuity of each half of the double nucleus has been clearly 

 traced to an advanced cleavage stage. During late cleavage and in the early gastrula the 

 nuclei are still typically double; but certain irregularities which tend to disguise the double 

 structure occur with increasing frequency, and the segregation of the maternal and paternal 

 chromatin cannot always be demonstrated. The hypothesis of individuality of the germ- 

 nuclei as applied to those species in which there is a mingling of maternal and paternal chromo- 

 somes is discussed, and supported by considerations regarding the persistent individuality of 

 the chromosomes. [See also Bot. Absts. 4, Entry 771.] — Bertram G. Smith. 



