KONGL. SV. VKT. AKADEMIENS HANDLING Ali. BAND 34. N:0 I. 19 



slightly cvliiidi'ical or iilmost iilobulai'. Di.-uaetcr U,oii to 0,os luilliui. As I luive seen 

 ak'ohol-j)reser\ed specimens only, I am uniil)Ie to decide whether the chromatophores are 

 green or yellow. 



I'yrocystis hamulus. N. Sp. 

 rUitc VII. Fig. 23. 



Tlii.^i eliaracteristic cysta, perhaps a stage in the development of some dinofliigellate, 

 seems to he akin to Pyroc. lunula. It is remarkable for the small body, that suddenly 

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

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

 Ijlanktou. 



Xauthidium paucispinosuiu. N. Sp. 

 I'hite VII. Fig. 24. 



This cysta is prol)aI)ly the same as has been figured by Hensen (S*" Ber. d. Kieler 

 kommissioii, Pi. IV, fig. ol) as dornige cyste. I have met with it both oft' the N. 

 coast of South America and at the Azores. 



V. DIATOMACE^. 



Asterionolla notata Gkun. 

 Plate VII. Fig. 32. 



Grunow has figured a valve and t-wo frustules of this species (Van Heuuck Synopsis, 

 PI. LII, fig. 3), whieli I hiwe found in samples from the Azores. The frustules are con- 

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

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



Asteroniphalus atlanticus Cl. and As. lieptactis Rlfs. 



Plate VIII. Fig. 69. 



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

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

 wiiich I supposed to be A. Brookei Bail. Later, 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. atlanticus. Gkan (Den Norske Nordhavs Expedition 1876 78. 

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

 publication (lagttagelser over overfladvandets temperatur, saltholdighed og plankton fra 

 Islandske og Gronlandske skibsrouter in 1898, pag. 52) Ostenfeld means, that A. atlanticus 

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



