Algae. 289 



Danske Videnskabernes Selskabs Forhandline^er. Nf'. 4. p. 339— 355. 

 pl. I. Köbenhavn 1910.) 



Exemplare von Ophioglypha textuvata aus Limfjord in Däne- 

 mark und der Westküste Schwedens zeigten bisweilen hier und 

 da eine grüne Farbe. Es zeigte sich, dass diese grüne Farbe von 

 einer neuen parasitischen Alge, Coccomyxa Ophiuvae Rosen v. n. sp. 

 herrührte. Die Alge ist parasitisch und verursacht Krankheiten und 

 zuletzt den Tod des Wirtes. 



In einer antarctischen Rhyiichocidaris friplopora wurden einige 

 farblose, parasitische Zellen gefunden, die als neuer Gattung: 

 Echinophycus niirabilis Morts. beschrieben wird. Die unvollständig 

 bekannte Pilanze gehört vielleicht zu den Myxomyceten. N.Wille. 



Oestpup, E., Danske Diatomeer. (XIII. 323 pp. 5 pl. Kjöben- 

 havn. C. A. Reitzel, 1910. Danish with English summary.) 



During 20 years the well known Danish diatomist E. Oestrup 

 has studied the diatom flora of Denmark, and the result of his 

 researches has now been published. 



The book is written in Danish, but there is a large English 

 summary and the descriptions of the new forms are in Latin; thus 

 the paper is accessible also to foreign readers. 



The paper is based upon the examination of 1402 samples from 

 the different Danish country parts; most of the samples are from 

 freshwater. only 287 being taken along the coasts; plankton diatoms 

 are omitted. As the treatment of the samples betöre examination 

 lias been the usual chemical one, nothing is to be found in the 

 paper concerning the plasma, chromatophores etc. of the living 

 cells. All the descriptions affect only the skeleton of the diatoms. "^ 



The author follows Schutt in dividing the diatoms in two 

 underclasses, Pennntae and Centvicae, but the first underclass has 

 been arranged in a new manner which partly is due to the late H. 

 van Heurck, partU'^ to the author: 



Sj'stem of Diatomaceae Danicae. 



1. Structure of the valve pinnate, frustule with three axes 



Pennatae Schutt ... 2. 



Structure of the valve concentric, radiate or irregulär, frustule 



with one rarely with three axes Centricae Schutt. 



2. Valve with a raphe Raphideae ... 3. 



Valve without a raphe Arraphideae. 



3. Raphe conspicuous Eurnphideae ... 4. 



Raphe more or less covered . . Kalyptoraphideae ... 5. 



4. Raphe on both valves . Diraphideae. 



Raphe on hypotheca only ........ Monoraphideae. 



5. Raphe long, extending throughout the entire valve. . . 6. 

 Raphe short, developed on the apices only Brachy raphideae. 



6. Raphe situated along both margins of the valve Eschaioraphideae. 

 Raphe not situated along both margins of the valve . . 7. 



7. The two branches of the raphe extending from apices along 

 the ventral margin of the valve, in the middle ascending towards 

 the dorsal margin and there meeting and forming an angle 



Gony raphideae. 



Raphe situated upon a keel Tropidoraphideae. 



Within these groups we find in the paper artificial ke5^s to the 

 genera, short descriptions of the genera and artificial keys to the 

 species as far as they have been found in Denmark. Under each 



Botan. Centralblatt. Band 116. 1911. 19 



