M 4 



OVI, l*\l I.SKN. 



In nil Ihe specimens seen by me the anlapical horns were long 

 mul hollow, so Ihnl, strange lo lell, the arctic sj)ecies P. pardllcluin 

 Hroch was not found in (he present material. 



P. dcprcssnm was i'ouiul in single sj^ecimens only in the neigh- 

 hourhootl ol" the coasl, lepeatedly but rarely in the pack-ice and in 

 the open sea. 



1) i si ril), liorcal oceanic species, widely dislrihiitcd. 



W). Peridinium oceanicum Vanhöllen, in Grönl.-Exp. d. Ge- 

 sellsch. für Krdk. zu Herlin II, 181)7, tab. V, lig. 2; Paulsen, Nord. 

 Plankton, p. 54, lig. (39. 



var. tijpicum Broch, Nyt Magaz. f. Naturvid. Christiania, 44, 

 1900. fig. a. 



Found as a single cell in the open sea outside the ice. 



1)1 s tri I). Oceanic tioreal species. 



20. Peridinium conicoides Paulsen, Meddel. Ira Kommis, i'. 

 Havundersøg. Ser. Plankton, Bd. I, Nr. 3, 1905, p. 3, üg. 2; Nord. 

 Plankton, p. öS, fig. 75; Broch, Spitzbergen Plankton, j). 53. 



Not rare in several samples from the coastal water and the 



pack-ice in 1908. 



Dis tri I). Arctic nerilic s])ecies, known from Iceland. Spil/.bcrf^cn and 

 (ireenland. 



21. Peridinium sp. 

 A small species (length 20 u) represented in lig. 14 was found 

 in three samples from Danmarks Havn in 1907. I suppose it is a 



young stage of the precee- 



ding species. In favour of 

 this conception speeks: the 

 whole form of the bod}^ 

 with convex outlines, the 

 small hollow protuberances 

 distant from each other, 

 the orbicular girdle and the 

 characteristic curvature of 

 the longitudinal furrow's 

 left margin. On the other 

 hand, the number and ar- 

 rangement of the plates do 

 not permit to unite the two species at once. There is only one 

 intercalary plate, as illustrated in fig. E, at least I have not been 

 able to find any sutures to separate between ;-, o and s. 



22. Peridinium subinerme Paulsen, Plankton invest. Iceland 



Fig. 14. Peridinium sp 



