KONGL. SV. VET. AKADEMIENS IIANDUMiAK. ISAM) 34. V<> I. 1!) 



slightly uyliftdrical or almost globular. Diameter 0,ofl to 0,o£ inillim. A> I have seeu 

 alcohol-prcserved specitncns only, I am unable to decide whether the chromatophores an 

 green or yellow. 



Pyrocystis haniulus. N. Sp. 

 Plate VII. Fig. 23. 



This characteristie cysta, perhaps a stage in the development of sorae dinoflagellate, 

 seems to be akin to Pyroc. lunula. It is remarkable for the small body, that suddenl) 

 goes över in two long, towards the distal part bent horns. I have found it in samples 

 from the Indian ocean and in the Atlantic between 12° — 32° N., 47° — 74° W., in desmo- 

 plankton. 



Xauthidium paucispiiiosum. N. Sp. 

 Plate VII. Fig. 24. 



This cysta is probably the same as has been figured by Hensen (5 tc Ber. d. Kieler 

 kommission, Pl. IV, tig. 31) as »dornige cyste», I have met with it both off the N. 

 coast of South America and at the Azores, 



V. DIATOMACE^E. 

 Asterionella notata Grun. 



Plate VII. Fig. 32. 



Grunow has tigured a valve and two frustules of this species (Van Heukck Synopsis, 

 Pl. LII, fig. o), which I have found in samples from the Azores. The frustules are con- 

 nected by their basal part to comb-like colonies, which are twisted in different ways. 

 Besides, the frustules in one colony are frequently directed in various directions. 



Asteromphalus atlantieus Cl. and As. heptactis Elfs. 

 Plate VIII. Fig. 6— {). 



In the year 1873 I published a figure of an Asteromphalus (Bih. till Kongl. Sv. 

 Vet.-Akad. Handl., I, n:o 13, Pl. IV, fig. 19), found in bottom-mud from Davis Strait, 

 which I supposed to be A. Brookei Bail. Låter, in 1896 (Bih. till Kongl. Sv. Vet.-Akad. 

 Handl., Vol. XXII 3, n:o 4, pag. 5) I proposed to name this form, which occurs in the 

 northern Atlantic, A. atlantieus. Gran (Den Norske Nordhavs Expedition 1876 — 78. 

 Protophyta 1897, Pl. IV, fig. 63) has given a good figure of the same form. In a recent 

 publication (Iagttagelser över overfladvandets temperatur, saltholdighed og plankton fra 

 Isländske og Grönlandske skibsrouter in 1898, pag. 52) Ostenfeld means, that A. atlantieus 

 is a small form only of A. heptactis. This opinion seems to me to be erroneous, 



