Biologie. — Cytologie u. Befruchtung. 53 



müsste und, soweit untersucht, auch ist, findet sich Vegetation. 

 Verf. citirt eine Analyse von Ball, nach welcher eine In- 

 krustation von Kalkgestein des Randes der Oase Kurkur bei 

 As SU an enthielt: 64,90% in Wasser lösliche Stoffe und unter 

 diesen 47,07% Na^ SO4, 19,03 Na Cl, 23,06 Mg SO4, 8,04 Ca 

 SO4. Eine Probe der 40,7 17o wasserlöslichen Teile der Efflor- 

 essenz am Oasengrund ergab: 61,02''/o Na Cl, 28,09% Na2 SO4, 

 9,09% Ca SO4. Büsgen (Hann. Münden). 



Allen, C. E., Spindle Formation in the Pollen mother- 

 cells of Larix. (Science. Mch. 1902. Vol. XV. p. 459.) 



A fibrous System can be traced from a reticulated stage 

 up to the completed spindle. Particular interest attaches to 

 this early reticulated stage, the later formation of a felted zone 

 about the nucleus, then a multipolar spindle which gradually 

 becomes bipolar, being essentially as described by Belajeff 

 and Strasburger. No centrosomes could be distinguished. 



Charles J. Chamberlain (Chicago). 



Allen, C. E., The early stages ofSpindle-formation 

 in the Pollen- Mother-cells of Larix. (Annais of 

 Botany. XVH. 1903. p. 281—312. pl. XIV and XV.) 



The origin of the spindle is traced from the fibrous sub- 

 stance of the cytoplasm. At first irregularly disposed, they 

 becom.e radially arranged round the nucleus, then they become 

 folded so as to form a zone concentric with the nucleus, and 

 simultaneously there is a marked increase in the amount of 

 intranuclear fibres, which appear to originate from a substance 

 within the nucleus itself. Gradually the fibres of the extra 

 nuclear zone become pulled out in various directions so as to 

 form a multipolar spindle. The latter is a transient condition 

 and ultimately the spindle commonly becomes diarch, but the 

 polar convergence is rather towards regions than to wards points. 

 In fact centrosomes are not present. Thus the spindle as a 

 whole is partly of cytoplasmic, partly of nuclear origin. The 

 author does not consider the fibres to represent protoplasm 

 strained along lines of force^ but as organised bodies that differ 

 chemically and physically from the surrounding protoplasm; he 

 thinks they probably originate from a „distinct fibre-substance". 



J. B. Farmer. 



COKER, W. C, The nucleus of the spore cavity in 

 prothallia of Marsilia. (Botanical Gazette. February 

 1903. Vol. XXXV. p. 137—138. F. 3—6.) 



Calls attention to the sending out of peculiar processes 

 from the intersporic nucleus toward the prothallium suggesting 

 a special modification for the transference of food material. 



Moore. 



