ÖFVERSIGT AF K. VETENSK.-AKAl). FÖRHANDLINGAR 1900, N:0 8. 927 



all saniples from 37 S. 23° W. to 34' S. 89^ K. This species 

 occurs thus as plentifuUy in tlie styli-plankton of the soiithcrii 

 as of the northern Atlantic. 



Peridiuium pedunculatiiui ScHÜTT. (Ergebn. d. Plankton- 

 Exp. Peridinéen PI. XIV f. 47) occurred sparingly between 34° S. 

 29° W. and 38 S. 20 W., also at 36^ S. 89° E. 



Peridiniuiu pelliicidum (Bergh) Schutt. This species, which 

 occurs in the Arctic Sea, was found in samples from 43" S. 1° E. 

 to 43° S. 57° E., always sparingly. 



Diatomaceae. 



Asteromplialus Hookeri Ehb. (1844). To judge from the 

 frequent occurrence in the antarctic regions, this species may be 

 the same as occurred in most of my samples. My specimens 

 agree completely with the form which I, in 1873, found in 

 bottora-mud from Davis's Strait and considered as A. Brookei 

 Bail. (Cleve, Bih. Sv. Vet. Akad. Handl. I. No 13 p. 10 Pl. 

 IV fig. 19), låter, in 1896, named A. atlanticus (Bih. K. Sv. 

 Vet. Akad. Handl. XXII. Part III N. 4 pag. 5), a name 

 that was adopted by Gran (D. Norske Nordhavs Expedition 

 1876—78, Botanik, protophyta 1897 Pl. IV f. 63). It was 

 recently confounded by Ostenfeld with A. heptactis (lagttagelser 

 över overfladvandets temperatur, saltholdighed og plankton 1898 

 p. 52). 



I have proved the specific difFerence of A. atlanticus and 

 A. heptactis (K. Sv. Vet. Akad. Handl. XXXIV N. 1 p. 19) 

 and stated the identity of A. atlanticus and A. Hookeri. Gre- 

 VILLE (Trans. M. Soc. vol. VIII p. 114 1860) considered the 

 Ehrenbergian species A. Bruchii, A. Cuvierii and A. Hum- 

 holdtii as identical with A. Hookeri, which opinion was accepted 

 by Rattray (A revision of the genus Coscinodiscus. Proc. Roy. 

 Soc. Edinburgh 1890 p. 208). The A. chaUengerensis, A. Ro- 

 perianus var. atlanticus and A. antarcticus Castr. (Rep. Challeng. 

 Diat. 1886 Pl. V. f. 2, 3; Pl. XVI f. 11) seem to represent the 

 same species. A. reticulatus Lemmerman (Abh. Nat. Ver. Brem. 



