Marine Plankton from the East-Greenland Sea. 



307 



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



e are named ;-, o and c, which is more appropriate than in Kofoid's 



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



3". The antapicals are named by Broch A and B 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. 



Fig. 4. Diagram of plates of Peri- 

 dininm. 



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

 undersøgelser. Ser. Plankton. Bd. I, No. 5. 1907, p. 12, fig. 12; 

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

 Schröder) Broch, Arch. f. Protistenk. 22. 191U, p. 183. 



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

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



5*ii 1907). I think Broch is not right 

 in uniting this species with P. quar- 



' — V / — >L '\ nerense, he does it because of the 



resemblance in the arrangement of 

 A ^ B \ c ijjç plates of the two species, taking 



Fig. 5. Peridinium Cerasus. 37ö t. m. a reservation on 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. 



Distrib. Known Ironi the North Sea and Iceland. 



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

 p. 23, fig. 9; Xord. Plankton p. 44, fig. 53.— ? P. ovatum Fauré- 

 Fremiet, Ann. sc. nat. zool. 9. ser. 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. 



Distriti. Boreal-neritic and arctic species, known trom Norway and 

 Iceland. 



