Marine Plankton from the East-Greenland Sea. 



307 



the left (descending screw). The intercalaries neighbouring c, d and 



e are named y, о and s, which is more appropriate than in Kofoid's 



system where 3", 4" and 5" are neighbours to respectivety 1°, 2° and 



3°. The antapicals are named by Broch A and В and the post- 



cingulars I — V. It seems to me that 



if we here change letters to Roman 



numbers and vice versa we get a 



more practical mode of designation. 



Then, the apicals will be 1—4 and 



the antapicals I — II, the precingulars 



a — g and the postcingulars A — E. 



Thus, we have letters along both 



margins of the girdle and numerals at the top and at the bottom. 



Fig. 4 illustrates this method of denominating. 



Diagram of plates of Peri- 

 dinium. 



7. Peridinium Cerasus Paulsen, Meddel. Kommis, for Hav- 

 undersøgelser, Ser. Plankton, Bd. I, No. 5. 19Ü7, p. 12, fig. 12; 

 Paulsen, Nord. Plankton p. 43, fig. 52. vix P. qiiarnerense (Br. 

 Schröder) Broch, Arch. f. Protistenk. 22. 1910, p. 183. 



Fig. 5 represents a specimen (36 /^ long) of P. Cerasus which species 

 was found rather rarely in a single sample from Danmarks Havn (Sept. 



5th 1907). I think Broch is not right 

 in uniting this species with P. quar- 

 nerense, he does it because of the 

 resemblance in the arrangement of 

 ^ ' '^ в I с ijjç plates of the two species, taking 



Fig. 5. Peridinium Cerasus. 375 t. m. a reservation ОП account of the in- 

 completeness of my figures of P. Cerasus. In any case, my figures 

 are clearly showing that P. Cerasus has a long and well marked 

 apical horn, while P. quarnerense has a short one, and just this 

 horn is the characteristic of P. Cerasus. The dimensions of P. quar- 

 nerense are unknown, so in this respect it cannot be compared with 

 P. Cerasus. 



13 i strib. Ivnown trom tlie Nortli Sea and Iceland. 



8. Peridinium roseum Paulsen, Plankton invest. Iceland 1903, 

 p. 23, fig. 9: Nord. Plankton p. 44, fig. 53.— ? P. ovalum Fauré- 

 Fremiet, Ann. sc. nat. zool. 9. sér. 1908, p. 218, fig. 5, tab. XV, fig. 6, 

 non Pouchet. 



Found in several samples from the pack-ice and Danmarks 

 Havn, mostly in rather few specimens. 



I^istritj. I^oreal-neritic and arctic species, known from Norway and 

 Iceland. 



