ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 709 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including Cell Contents. 



Cytological Studies and Heredity.* — E. Strasburger and three of 

 bis pupils have published together a series of papers which are repub- 

 lished under a common title of " Histological Contributions to the 

 Question of Heredity." Strasburger's paper is a general one, and deals 

 with a comparison of typical and allotypic divisions, the two divisions 

 formerly called heterotypic and homotypic being included under the 

 latter term. C. E. Allen has a paper on the exact behaviour of the 

 nuclear material during synopsis in Lilium canadense. Miyake follows 

 with observations on the reduction division in the pollen-mother-cells of 

 some Monocotyledons, and there is a final paper by J. B. Overton on 

 similar divisions in some Dicotyledons. 



Kinetic Centres in Plants.j — C Bernards publishes a further paper 

 on the attraction spheres of plants. The work is largely concerned in 

 answering the attacks of Koernicke on the author's earlier paper. He 

 considers it illogical to admit that centrosomes exist in so many groups 

 and yet are absent in Phanerogams. He holds that the bodies he 

 observed are not to be confounded with extra-nuclear nucleoli, and 

 that the existence of a kinetic centre within a zone of dense kinoplasm 

 must be admitted for Angiosperms. 



Nuclear Divisions in Endosperm.! — B. Sypkens has investigated 

 nuclear division chiefly in the parietal layer of the embryo-sac in 

 Fritillaria, and in a few other cases of Vegetative division, and a sum- 

 mary of his results is given by J. W. Moll. The author's results 

 mainly confirm those of Van Wisselingh, (Iregoire, Wygaerts, and 

 Berghs. He finds no evidence for the existence in the nuclear network 

 of two elements, linin and chromatin, and he believes in the individuality 

 of the chromosomes both in the resting and the spireme condition. The 

 author further concludes that the nuclear spindle is entirely formed 

 from the cytoplasm within the nuclear space, but the most important 

 contribution in his paper deals with the relation of the spindle to cell- 

 wall formation, in which he shows that the latter process often takes 

 place without any connection with spindle formation. 



* Jalirb. wiss. Bot.. xlii. (1905) pp. 1-1.*):; (7 pis.). 



+ Joum. de Bot , xix. (1905) pp. 80-88, and pp. 89 -!»7 (1 pi.). 



% Kronikl. Akad. Weteuschapp. Amsterdam, vii. (1905) pp. 41 -1- 19. 



