;u(i 



Ovi I'ai:i,si;n. 



Tilis spc'fies was found .sj);iiiii[j;Iy iii few samples (Vom llic 

 pac'lvice and Ihc coastal waler. 



Di s Ir i I). Arctie species, known Ironi S|)it/.l)erji;en and Iceland. 



12. Peridinium pyriforme Paulsen, Meddel, fra Kommis, for 

 Havundersog. Ser. Plankton, Bd. 1, No. 5, 1907, p. VA, fig. 15; 

 Nord. Planklon p. 4(5, fig. 57. P. Steinii Jørgensen /. pyriforniis 

 Paulsen, Meddel. Kom. Havund. Ser. Planklon Bd. 1, No. 3. 1905, 

 p. 4, fig. 3d— e. 



Fig. 8 shows a species which was fairly common in some 

 of Ihc samples taken in August 1908 in Ihe open water out- 

 side the pack-ice, and which I 

 cannot refer lo any other spe- 

 cies than P. puriforme. Length 

 42—52//. It dillers from P. breve 

 by the taller form, the irregular 

 position of the intercalary à, 

 which in P. breve is regular 

 (Broch 1. c.) and in the very 

 narrow rhomb-plate, but, as sla- 

 ted above, these two species are 

 closely allied to each other. 



On the other hand, our spe- 

 cies is nearly related to P. Steinii 

 Jørgensen. As to the arrange- 

 ment of the plates (see fig.SD, E) 

 they are nearly identical, so the precingular a is small, the rhomb- 

 plate] narrow% and the intercalary o has an oblique position (Kofoid in 

 Arch. f. Protislenk. 1909, Taf. 2; Broch, Spitzbergen Plankton p. 49, 

 Broch in Arch. f. Protistenk. 1910, fig. 4}. Our species difïers from 

 P. Steinii in its much thicker and shorter form and in the thecal 

 wall being reticulate and not porulate as in P. Steinii. Broch says 

 (Spitzb. PI., p. 49): "ein näheres Studium von Peridinium pyri- 

 forme wird möglicherweise zeigen, dass die Individuen dieser Art 

 nur kräftig entwickelte Exemplare von Peridinium Steint sind." On 

 the other hand, Kofoid (1. c. p. 39) declares P. pyriforme not to be 

 identical with P. Steinii. 



Anyhow, it seems lo me lo be the best to keep the tw^o species 

 distinct at any rate provisionally until further evidences may come 

 lo hand. 



D ist rib. Boreal oceanic species, known from the northern Atlantic 

 and its tributaries. 



C UV D -~ ' E 



Fif^. 8. Peridinium puriforme. 37.') t. m. 



