Descendenz und Hybriden. 387 



diie only to the temporary Splitting of their ends. The time 

 of transverse fission is variable, taking place before the meta- 

 phase is completed or at the commencement of the contraction 

 of the spindle fibres. As the chromosomes move towards the 

 equatorial plate the longitudinal fission becomes more clearly 

 apparent in each limb. The author discusses the bearing of 

 the transverse qualitative division on the Mendelian theory, 

 referring particularly to the work of Sutton on Brachystola, 

 of Hacker on Cyclops, and Rosenberg on Z)/'öse/'ö hybrids. 

 He concludes that each tetrad consists of two Univalent chro- 

 mosomes one of paternal and one of maternal origin. He finds 

 that the sterility of race hybrids of Lathyrus odoratus is due 

 to the degeneration of the pollen mother cells, and suggests 

 that the union of the chromosomes in the synapsis is such as 

 to prevent any subsequent Separation. m. Wilson (Glasgow). 



Bateson, W. and R. P. Gregory, Onthe Inheritance of 

 Heterostylism in Primiila. (Proceedings of the Royal 

 Society. B. Vol. LXXVl. 1905. p. 581.) 



The experiments described deal with crosses between 

 different forms of Primiila sinensis. The short styled form 

 was found to be an ordinary Mendelian dominant to long styled, 

 with the exception of a Single short styled plant and its seif 

 fertilised offspring, which, when judged by the female gametes 

 v,ere ordinary heterozygotes, while their male gametes were 

 found to be bearing almost exciusively the dominant character. 



The equal styled condition (anthers at the same level as 

 the short style) was found to be associated with an extensive 

 spreading of the central yellow eye The latter condition is 

 recessive to the normal type and is transmitted independently 

 of length of style; but when it is developed in plants which 

 by gametic Constitution would be long styled, the equal styled 

 condition is produced. 



Experiments in double fertilisation gave discrepant results, 

 chiefly owing to the difficulty of applying the two sorts of 

 pollen to the same style under uniform conditions. 



R. H. Lock. 



BiFFEN, R. H., Experiments with Wheat and Barley 

 Hybrids illustrating Mendel's Laws of Heredity. 

 (Journ R. Agric. Soc. England. Vol. LXV. 1904. p. 337 

 —345.) 



A Short account is given of Mendel's experiments with 

 peas, and the case of both mono- and di-hybrids are illustrated 

 by concreto examples drawn from experiments in crossing 

 different strains of wheats and barleys. The importance to 

 practical breeders of a knowledge of the Mendelian principals 

 is pointed out. R. H. Lock. 



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