72 SUM.MARY OF CURRENT RESEARCHES RELATING TO 



important genera. Certain interesting forms are discussed, notaV)ly 

 Heiiniella excentrka, which is covered with coccoliths ; Sijracosphsera 

 prolongata ; and the diatoms Brenneckella lorenzinl and B. Kohli, which 

 form a colony with Pontosphsera sessilis. E. S. Gr. 



Quantitative Investigations of Formations of Organisms on the 

 Surface of Water : I., Euglena sanguinea. — E. Naumanx (Infprn. 

 Rev. Ges. ffydrobiol. a. Hydrogr., 1915-16, 7, 214-21, 4 pis. ; see 

 also Bot. CentralbL, 1918, 137, 391). The species in question. E. 

 sanguinea, forms a bright to l)rown-red cover over the entire surface of 

 the water, and along quiet, banks it lies in red streaks. In quiet bays 

 Eiiglena forms small red patches on the surface. The species which 

 form this mass in the ponds of Aneboda in South Sweden are 

 enumerated. E. S. (x. 



Common Diatoms. — Thos. K. Melloe {London .- W. Wesley and 

 Son, 1920, 16, pis. a-g). A series of seven plates containing 400 

 original drawings from all parts of the world, with an introduction 

 and a general index. The intention is to aid the amateur and to 

 popularize the study of Diatoms. A. Gepp. 



Green Oysters in Denmark in 1911-12.— C. G. J. Petersen 

 {Intern. Kerne ges. ffydrobiol. n. ffydrogr., 1915-16, 7, 39-41 ; see 

 also Bot. CentralbL, 1918, 137, 392). In the new cemented basin for 

 the storage of oysters in the' Limfjord in Denmark occurs Navicula 

 ostrearia both in blue-green and in colourless forms, which are connected 

 by intermediates. This alga is certainly not the cause of tl e green 

 colouring of the oyster-gills, for but few examples of it were found in 

 the intestine, and indeed it often passes alive through the oyster. Also 

 the alga was not plentiful in the basin. The colouring matter of the 

 diatom is known to be very easily extracted, while that of the oyster 

 gills is not dissolved by alcohol, ether, hot water or nitric acid, though 

 it loses its colour in an alkaline solution. The author believes that the 

 green colour of the oyster gills is not caused by digestion of N. ostrearia, 

 but rather from constituents in the water. E. S. Gepp. 



Bacillariales from the Neighbourhood of Wurzberg. — A. Mayer 

 {Kryptog. For.H'h. hrsg. Eager. Bot. Ges., 1917, 41-7 ; see also Bot. 

 CentralbL, 1918, 137, 310). A list of 102 species, three of which are 

 new to Bavaria : Diploneis oculata CI., Nitzschia apiculata Grun., and 

 A'". Claiisii Hantzsch. Many other rather rare species are recorded. 



E. S. G. 



Bacillariegs of the Jaszoe Fish-ponds. — I. L. Lacsny {Bot. 

 Xozlein., 1917, 16, 12-20, figs, in text; see also Bot. Centralbl., 1918, 

 137, 341). The two ponds in question lie in the Tapolcza valley in 

 the district Abauj Torna ; one of these is very shallow and covered 

 with "bloom." The author records eighty-two species, of which two 

 species and foui- varieties are new. The paper is written in Macvar. 



E.\S. G. 



