26(> H. c. OSTIM I I.D. 



190.'), I). 'M, li^. ;5;{; Osk'iilVld, Wiss. Erj^ehn. Aral-See Exped., VIII, 

 St. Petersburg, 1908, p. 140, |)1. 7, ligs. 4-5. 



In a sample IVoin the outer pari of the pack-ice a single dead 

 frusluce of this species was found. August 190(). 



Dislrib. Widely distril)ute(l oceanic sjjccics, accordinj^ to (iu.\N com- 

 mon, especially durinj^ winter, in the (Uilf-Stream area of the Norwegian 

 Sea and in the North Atlantic; not at home in arctic water. 



11. Coscinodiscus subbuliens Jorgensen, Bergens Museums 

 Skrifter 1905, p. 94, pi. VI, lig. 2; Gran, Nord. Plankton XIX, 1905, p. 32, 

 fig. .'}2; C. oculus iridis Gran, Fauna Arctica, III, Lief. 3, 1904, p. 519, 

 pi. XVII, figs. 17—19. 



The species which I refer to Jørgensen's C. subbuliens is very 

 common in some of the samples from the autumn, indeed forming 

 the main part of the phytoplankton. 



Owing to the abundance of material I have been able to add 

 some points to the descriptions given by Jørgensen and Gran. As 

 to the size of the species Jorgensen gives a diameter of "usually 

 50 — 100 /i", and Gran says 65 — 150 ,^;!, while my measurements extend 

 it to 240// (185« as mean of 20 measurements) for the normal vege- 

 tative cells. The valves are coarsely areolated in a radiate manner, 

 and in contradistinction to the descriptions of the two quoted au- 

 thors I have found that, at a certain adjustment, a single row of 

 very small points or apiculi are discernible a little inside the margin 

 and further, asymmetrically among them, two larger apiculi or knots, 

 at a distance from one another of between 120° and 150^. The 

 apiculi which are difficult to see, best upon ignified material moun- 

 ted in styrax-balsam, stand rather closely, as between two usually 

 3—4 radii of aréoles originate. The existence of the two larger 

 apiculi shows that C. subbuliens must be referred to the Group Bia- 

 piculati created by me in 1908 (W^iss. Ergebn. d. Aralsee-Exp., Lief. 

 VIII, St. Petersburg, 1908, p. 147). Further investigations must decide, 

 if all species of the sectio Radiati Rattr. possess these two apiculi; 

 hitherto they have been found in C. biconicus Van Breem., C. aralensis 

 Ostf., C. Granu Gough, C. centralis Ehrbg. and C. concinuus W. 



Gran (1904, fig. 19) has figured the construction of the girdle of a 

 specimen which just has divided into two daughter-cells and where 

 the matter is more complicated than in the ordinary cells. Therefore 

 I have given a figure (Fig. 2) showing the girdle of a normal cell K 

 This figure represents only a part of the girdle, but it is seen di- 

 stinctly, that in the connecting part of each valve two structure-lines 



* Tlie fig. 32 c in Grans paper of 190Ô is not quite clear in tliis respect. 



