554 Alsae 



fe' 



enumerated in the plankton lists pablished bj^ the International 

 Cooperation for the Study of the Sea during the years of 1902—1909. 

 Only the true plankton forms are mentioned and the rarer of those 

 not treated in detail Further several critical species (e. g. Chaeto- 

 ceras sect. Borealia and the genus Coscinodiscus) are omitted, as it 

 has not been possible to rely upon the identifications given in the 

 lists The foUowing 71 species are more thoroughl}^ studied: 



A. Pennatae: Thallassiothrix longissima, Th. )iits5chioides, Th. 

 Fvauenfeldii, Asterionella japonica, A. formosa var. gracillima, Navi- 

 cula menibranacea and Nitsschia seriata. 



B. Centricae: Melosira Borrevi, M. hyperborea, Pavalia sulcaia, 

 Stephanopyxis turris, Sceletouema costatiun, Thalassiosira baltica, 

 Th. Nordensköldii, Th. gravida, Lauderia borealis, Leptocylindrus 

 danicus, Guinardia ßaccida, Actüiocydus 'Ehrenbergii, Actiiioptychus 

 tindulatus, Rhisosolenia Stoltevfothii, Rh, Shrubsolei, Rh. setigeva, 

 Rh. hebetata, Rh. calcaravis, Rh. stylifonnis, Rh. alata, Corethron 

 criophiliim, Bacteriastnirn varimi^, B. delicatuliim , Chaetoceras atlan- 

 ticurn, Ch. decipiens, Ch. teres, Ch. Lauderi (Syn. Ch Weissßogii)^ 

 Ch. contortum, Ch. didymuni, Ch. consMcttini, Ch. affine (Syn. Ch. 

 SchiUtii), Ch. laciuiosum, Ch. breve, Ch. diaäentn, Ch. seiracanthinn , 

 Ch. coronatiini , Ch. holsaticuni, Ch. siniile, Ch. subtile, Ch. Wighainii, 

 Ch. secnndum (Sjm. curvisetimi) , Ch. debile, Ch. auastomosaiis, Ch. 

 scolopendra , Ch. cinctuin, Ch. fiircellatuni , Ch. sociale, Ch. radians, 

 Eucanipia zodiaciis, Streptothecn thajnensis, Cerataidiua Bergonii, 

 Biddulphia auvita, B. mobiliensis. B. sinensis, B. granulata , Belle- 

 rochea mnlleus and Dityliinn Brigliiwellii. 



Under each species are given: 1. General features of distribu- 

 tion and biology; 2. Distribution within the regions investigated 

 (occurrence, both geographical and seasonal; relations to the hydro- 

 graphical conditions, i.e. temperature and salinity; anomalies in the 

 occurrence); 3. Summarj-, and Observations still to be made. 



The distributions of the more important 46 species within the 

 regions investigated (English Channel, North Sea.Skager 

 Rak, Kattegat, Baltic, Norwegian Sea, Faero-Shetland 

 Channel, coastal waters of Iceland, and Murman Sea) are 

 given on 39 quartocharts, each of which consists of 4 smaller Charts 

 representing the distribution at the four quarter months (Februar}-, 

 May, August, November). On the Charts the different relative quan- 

 tities of the species according to the common!}'' used plankton 

 Symbols are shown b}^ different signs. 



The paper shows that the geographical and seasonal distribu- 

 tions of the plankton diatoms of ithe sea off Nort-western Europe 

 are now fairly well known, but that our knowledge of the biology 

 is still v^ry poor. The same is the case with regard to the develop- 

 ment (life-cycle) of all plankton diatoms. 



Some systematical and nomenclatorial remarks are added. 

 especially with regard to the species of the difficult genus Chaeto- 

 ceras of which 25 species are mentioned. Author's abstract. 



Ostenfeld, C. H., Schi'sophyceae, in: Resume plan k ton ique. 

 3. partie. (Bull, trimestriel etc. public par le Bureau du Conseü 

 perm. intern, pour l'explor. de la mer. p. 509—514. Copenhague 1913.) 



This paper is a part of the working up of the numerous records 

 found in the plankton lists published by the International Coopera- 

 tion for the Study of the Sea during the years 1902—1909. 



