Palaeontologie. — Algae. 221 



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Calymmathotheca bifida Lindl. & Hutton sp. Sphenopteris sp., 

 Sp/ieuopfiyllum tenerrimum Ettingshausen var. etongatum D. White, 

 Asterocalamites scrobiculatus Schlotheim sp., Lepidodendron spetsber- 

 gense Nathorst, Lepidendron 3 species indeterminatae, Lepidoplixl- 

 lum cfr. lanceolatum Lindl. & Hutton, Stigmaria ficoides Sternberg sp. 



C. Ferdinandsen. 



Danforth, C. H., Periodicity in Spirogyra. (Rept. Missouri Bot. 

 Gard. XXI. p. 49-59. Dec. 22. 1910.) 



Various species of Spirogyra were subjected to the Solutions 

 used by Benecke to induce zygospore formation. It would appear 

 that there are specific differences as regards the reactions of fila- 

 ments and zygospores in the species studied, and that Benecke's 

 conclusions based on the reactions of 5. communis, are probably 

 not of general application, or are applicable only under very special 

 conditions. Moore. 



Ostenield, C. H. and O. Paulsen. Marine Plankton l'rom the 

 East-Greenland Sea. (W. of 6° W. Long and N. of 73° 30 X. 

 Lat.) collected during the "Danmark Expedition" 1906 — 

 1908. IV. General Remarks on the microplankton. (Medd. 

 om Grönland, XLIII. 11. p. 319—336 with tables and a sketch- 

 map. 1911.) 



The papers by the above named authors containing the syste- 

 matical lists of the organisms of the microplankton have been noted 

 in earlier reviews. Now the general remarks on the character of 

 microplankton have been published. 



The plankton of the Danmarks-Havn is an arctic neritic 

 coast plankton with a flowering period of short duration in late 

 summer. It is poor in species and consists mainly of neritic diatoms 

 which have a wide distribution in northern seas; truly arctic are 

 only few species of it. 



The summerplankton of the pack-ice and coastal waters outside 

 the East Greenland coast may be referred to three regions: 1. 

 Innermost the plankton region of the coastal waters characterized 

 by diatoms (Chaetoceras ssp., Coscinodiscus subbuliens). 2. The plankton 

 region of the pack-ice (Cyttarocylis denticulator , Rhisosolenia ssp., 

 etc. . 3. The plankton region of the open water with small quanti- 

 ties of characteristic species. The plankton region of the pack-ice 

 corresponds to the East Icelandic Polar Cttrrent, whilst the plankton 

 region of the coastal water corresponds to the coastal waters mixed 

 with those from ihe melting snow of the landj; the plankton region of 

 the open water may probabl}* be referred to the circulating central 

 area of the Greenland sea. C. H. Ostenfeld. 



Palmer, T. Ch., The mechanism of diatom motion. (Proc. 

 Del. Co. Inst. Science. V. p. 100-112. Apr. 1910.) 



A general historical review of the subject with the conclusion 

 that "the living substance of the cell, more or less deeply overlaid 

 with coleoderm substance of varying consistency and itself assuming 

 that degree of fluidity which best meets the requirements of the 

 Situation, permeates the raphes, circulates in the keels, or in some 

 cases protrudes quite beyond the silica, and functions as the actual 

 propulsive agent." Moore. 



