Marine Plankton from the East-Greenland Sea. 



305 



Fig. 1. Dino- 

 physis arcti- 

 ca. 375 t. m. 



lower end (see the drawing), like those of D. acuminata. Newer- 

 theless I think it wonld be premature to unite these two species 

 Ü. arctlca having a much shorter and broader form. Jör- 

 GENSEN (Bergens Museums Aarbog 1900, No. Ill, p. 19) 

 names the species D. acuminata var. granulata. Length 

 3ß — 42«. — D. arctica was found in several samples from 

 the pack-ice and the open sea outside it, mostly few 

 specimens, and as single ones in the coast water and in 

 Danmarks Havn. 



Di st г ib. Arctic species. 



3. Dinophysis rotundata Claparède & Lachmann Mém. inst, 

 nat. Genevois 1859, p. 409, tab. XX, fig. 16; Paulsen Nord. Plankton 

 p. 17, fig. 18. 



Fig. 2 represents a cell with a very coarsely areolated wall and 

 broad intercalary band. The epitheca is relatively large, and obli- 

 que. This cell, w^hose length was 60//, is supposed 

 to be an old one. Other cells with finer areolated 

 surfaces were 40 — 52 /i long. From this it may be 

 seen that the arctic specimens are somewhat bigger 

 than those from southern waters, whose length was 

 given by Bergh and in Nordisches Plankton by me 

 as 48//. 



Dinophysis rotundata was found very sparingly 

 both in the coastal water, the pack-ice and outside it. 

 Distrib. lioreal oceanic species, widely distributed in tlie northern At- 

 lantic and its tributaries. 



Gonyaulax Diesing. 



4. Gonyaulax triacantha Jørgensen, Bergens Museums Aar- 

 bog 1899, No. VI, p. 35. Paulsen Nord. Plankton p. 28. 



A single specimen was found in a sample from the pack-ice 

 (1906) but a great many in a sample from Danmarks Havn in Sep- 

 tember 1907 (Water 0°). 



D i strit). Arctic ncritic species, known from Alaska, Iceland, West coast 

 of Norway. In the North Sea very rare. 



5. Gonyaulax sp. 



In some samples from the pack- 

 ice (1906) the little organism represen- ^ 

 ted in fig. 3 was found. Length 20 — 24//. 

 I have not succeeded in finding out its plates. In some cases the 

 surface was covered by a great-meshed reticulation of a simijar kind 

 as that figured by Klebs in Botanische Zeitung 1884 fig. 2 — 5 for 

 Glenodinium trochoideum (now. Peridinium trochoideum (Stein) Lem- 

 mermann). 



Fig. '2. Dinophysis 

 rotundata. ;57Г) t. m. 



В \-^^ С 



Fig. ;{. Gonyaulax sp. 37.") t. m. 



