• ZOOLOGY AND UOTAXV, MICROSCOPY, ETC. 505 



four stations are located within a branch of the Kuroshiwo current, and 

 the species enumerated in the report are mostly oceanic forms. Several 

 new species are described. 



Change of Colour in Oscillarieae.* — B. Schindler writes an ex- 

 haustive treatise on change of colour in Oscillariefe. His principal 

 results are as follows. 1. The species examined, Fhormidiwn autumnale 

 Gom., OscUlatoria formosa Bory, and Oscillaria limosa Gom., are dis- 

 tinguished by very pronounced changes of colour arising in ordinary 

 light. A particularly large variability of colour is shown by Pliormidium 

 avtumnaJe, which may become dark violet, dark red-brown, brown, 

 brown-yellow, or yellow. 2. Colour-changes according to the compli- 

 mentary chromatic adaption of Gaidukov was not observed. 3. The 

 colour-change of the Oscillariege observed depends on nutritive physio- 

 logical factors ; it is a result of the diminishing quantity of nitrogen, 

 owing to the growth of the filaments in the nutrient substratum. 

 4. The occurrence of colour-change in the species examined is therefore 

 a function of the height of concentration and the amount of the 

 nutrient medium. 5. The intensity of the light plays a more or less 

 indirect and accelerating part in the change of colour. 6. Regeneration 

 of the original normal colour is brought about by an addition of in- 

 organic compounds of nitrogen, all light being excluded. 7. The 

 ecological meaning of colour-change where there is a lack of nitrogen 

 lies in a prudent decrease of the colour material available for assimilation, 

 in order to avoid nutritive physiological disturbances. 



Hungarian Diatoms.t — J. Pantocsek publishes a list of the Bacil- 

 larieai of Lake Neusiedler. He records 149 species and varieties, of 

 which about 44 are new. The new genus Carnegia is described. 



Volvox.t — C. Janet writes a dissertation on Volvox. He gives his 

 views on the phylogeny of the stage w^hich he regards as a phytoblast, 

 preserved under the forms of Volvox, up to the present day. The genus 

 is cosmopolitan. He describes the structure of the adult individual, 

 gives an historical account of the genus, points out the differences 

 between F. gloicitor and V. aureus, discusses gonidia and meridia, and 

 other structural details. He describes also the cladodogonidia, the 

 androgonidia, and the gynogonidia. The phenomenon of asynchrono- 

 gony takes place frequently in monoicous species of Volvox, but more 

 generally proterandry, and more rarely proterogony. In V. glolator 

 autogony may sometimes occur. He then describes the development of 

 the ovum ; the rotatory movement of Volvox, and those of translation 

 and phototactism ; the method of nutrition ; exhaustion of the somatic 

 plastids ; death. A bibhography completes the memoir. 



New G-enus of Volvocales.§ — A. Korschikoff describes a new 

 genus and species, ^ipermatozoims exsultans, of the group Yolvocales. 



* Zeitschr. Bot., v. (1913) pp. 497-575. 



t Pozsony (1912) 48 pp. (4 pis.). See also Nuov. Notar., xxiv. (1913) pp. 100-1. 

 X Le Volvox. Limoges : Ducourtieux et Gout (1912) 151 pp. (figs.). See 

 also Nuov. Notar., xxiv. (1913) pp. 94-95. 



§ Ber. Deutsch. Bot. GeselL, xxxi. (1913) pp. 174-83 (1 pL). 



