Marine Plankton from tlie East-Greenland Sea. 



305 



lower end (see the drawing), like those of D. acuminata. Nev/er- 



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



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



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



names the species D. acuminata var. gramilata. Length f/l^^j 



36 — 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 figiöjno- 

 T>w 1 TT "^ ptiysis arcti- 



Danmarks Havn. ca. 375 t. m. 



Di st rib. 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 relativeh' large, and obli- 

 que. This cell, whose length was 60 ju, is supposed 

 to be an old one. Other cells with finer areolated 

 surfaces were 40—52// 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/^. 



Fig. 2. Dinophysis Dinophusis rotundata was found very sparinelv 



rotundata. .5/ot. m. i ^ j f tri j 



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

 D ist ril). Boreal oceanic species, widely distributed in the northern At- 

 lantic and its tributaries. 



Cronyaiilax Diesing. 



4. Gonyaulax triacantha Jørgensen, Bergens Museums Aar- 

 bog ltS99, 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°). 



Dis tri b. Arctic neritic 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- ^^^~-^-^ ß ^~ — ^ ^ 

 tedinfig. 3 was found. Length 20-24//. ^'S- '^- Gomjaulax sp. 37.') t. m. 

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

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

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

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

 mermann). 



