KONGL. SV. VKT. AKADEMIENS HANDLINGAR. BAND 34. N:o I. 1 .'i 



Trypanosphaera brachysiphon; N. Sp. 



Plate VI. Fig. 3. 



Shell a regular sphere. Pores of unequal si/.c; the larger prolonged in ;i verv sliorl 

 tube, with two or thrce teeth. 



Diameter: 0,is, of the larger pores 0,oi7 millim. 



Found very rarely at 56° N. 17° W. (November L898) and al 11 N. 66 W. (De- 

 cember 1898). Temperature 11,6 to 12. Salinity 34, eo to 35,25. 



III. DINOFLAGELLAT^E. 



Cératium (tripos var.) arcuatuin Gourret. 

 Plate VII. Fig. 1 1 . 



Gourret has described (Ann. du Musée d'Hist. Naturelle de Marseille; zool., Vol. I 

 1883 n:o 8, pag. 25, Pl. II, tig. 42) a form of C. tripos, which I consider, although with 

 a some hesitation, to be identical with the Atlantic form. 



It is rather common in the tropical Atlantic from 29° S. to 48° N. 



Cératium (tripos var.) arietinum. N. Sp. *) 

 Plate VII. Fig. 3. 



This form, which belongs to the tripos-type, is very constant and could be consi- 

 dered as a distinct species. I have seen it in samples from the Indian Ocean and the 

 Atlantic, chiefly on the area between the Azores, the Engl. Channel and New York. It 

 occurs besides, but sparingly, in the N. Equatorial current, the Antilles current and in 

 the Caribbean Sea. It belongs to the styli- plankton. 



Cératium (tripos var.) azoricum. N. Sp. 

 Plate VII. Fig. 6, 7. 



This form is nearly related to the typical C. tripos, but differs by smaller size and 

 short apical horn. It occurs round the Azores and W. of the Spanish Peninsula. I have 

 also met with this form in plankton from 25° S. 7° E. 



Cératium (furca var.?) belone. N. Sp. 

 Plate VII. Fig. 13. 



This form, which is evidently nearly akin to C. furca, is very rare in the Atlantic 

 and has been found in samples from 10° N. 53° VY. and 33°— 34° N. 15°— 12° W., thus 

 in the western and eastern tropical Atlantic. 



*) J0RGENSEN (Bergens Museums Aarbog 1899, X. VI, Pl. II, fig. 11) names this form Cératium tripos 

 arcuatum forma heterocampta. J0RGENSBNS work was not published when this paper was written. 



