Very rare : ytanisuiul r. ").! n loiii;. 



/>istiil>iitio)i: West coast of N'oiway. lioliuslaii (Sweden). 



KHiiii. IH40, Miki-ofreolo 



N. prætexta Ebrh. 

 1. lil, f. 28 < Piiniidaria p.). Van IIkihck Svn. 

 92. pi. IX, f. 18. 



l)(slnl,ii!ii,ir. ('ousts of Ww. North Sea. The Mediterranean. 

 Red Sea. Indian (_)eean. I'aeilic Ocean. Ea.st coast of America. 



A", lyni 1:miih. 

 I'il. pi. I. I, l', '.t. Van IIeihck Syiioix. 

 S. h/rii vm: Ehrenlcrii'u Cl. 1. c. p. «:J. 



10, f. 1. 



Not nnrre(iiient: Moskenstronnnen +• Stanisnnd r. Svolv;ei' r. 

 Raftsund r, Stene i'. 



Distriliiition: Coasts of the North Sea. The Mediterranean. 

 Ived Sea. Indian Ocean. Pacitie Ocean. Kerguelcn. Cape Horn. 

 America. 



iV. Hennedyi W. Sm. 

 \V. SM. Hiit. Iiiat. II. II. <«. A. SCHM. Nuids. Dial. pi. 1. l'. H. 



Very variable. 



Frequent: Stamsunde, tlie Ostnesliord r, Brettesnes— Slcroveu r, 

 Raftsund +, Stene r+. 



Dixfribiitioit: Coasts of the North Sea. Arctic regions. The 

 Mediterranean. Red Sea. Indian Ocean. Pacitie Ocean. Atlantic 

 Ocean. 



var. cireumsecta Gkun. 

 Grcn. in A. ScHM. Xonls. Diat. p. 89, jil. I, figs. 3t>, 42 (A\ puli/stkfa rar. cl. 



Frequent: Stamsund + c, Raftsund r, Stene -\-. 



Dii-tnbxtion : Coasts of the North Sea. Finmark. Tiie INIedi- 

 terranean. Red Sea. Indian Ocean. America. 



Besides, a fine variety from Stamsund, i', with short marginal 

 striæ between the main ones. 



A'', spectabilis Greg. 

 Greg. Diat. of Clyde p. 481, p!. IX, f. 10. A. Schm. Atlas, pi. .3, figs. 20—21. 



Though usually easily recognizable, this species is scarcely 

 distinct from all forms of the very variable iV. h/ra (cfr. Cl. 

 1. c. p. 60). 



Not unfrequent: Moskenstrommen r -|-, Stamsund r ^-. Svolva^r r. 

 Raftsund r, Stene r +• 



An analogous variety to that of X. Henneihjl. with more 

 numerous marginal striæ, occurs (Stene, r). 



Thshihdion: Coasts of the North Sea. Greenland. The 

 Mediterranean. Red Sea. Indian Ocean. Pacific Ocean. Cape 

 Horn. 



JV. abriipta (Grko.) Donk. 



DONK. lirit. Diat. p. 1.3, pi. II. I', fi. A. Scum. Novels. Diat. pi. 1, f. :i7. X Jijra 



rar. a. Grkg. Diat. of Clyde p. 486, pi. IX. figs. 14. U h. 



Frequent: Moskenstrommen r, Stamsund r, Svolvær -f- c. the 

 Ostnesliord c, Raftsund r, Stene +, Gaukværø +c. 



Distribution: Coasts of the North Sea. Finmark. Spitsbergen. 

 The Mediterranean. Black Sea. Red Sea. Indian Ocean. China. 



Somewhat rare: Moskenstrommen r, Stamsund r +, Svolvær +, 

 the Ostnesliord r, Stene r. 



DislrihHtiaii: Coasts of the North Sea. The Mediterranean. 

 Red Sea. Indian Ocean. Pacilic Ocean. America. 



mr. clliptica A. Scini. 

 A. Schm. Nords. Iliat. pl. I. r. H'.K Van Heuhik Synops, pl. 10, f. 2. 



Very frequent: Stamsund -| , Svolvær -f, Raftsund -|-, I5ret- 

 tesnes— Skroven r, Stene c, Gaukværø -\-. 



Distribution : Coasts of the North Sea. The :Mediterranean. 

 Red Sea. Indian Ocean. Philippines. 



var atlantica A. Scum. 

 A. Schm. Nords. Diat. \i\. 1, t'. .'M. 



Very characteristic. Recalls sometimes X ahniiita. but always 

 easy to distinguish from that species. 



Rare: Stamsund r +, Moskenstrommen r. 

 Distnhulion : Coasts of the North Sea. 



N. forcipata Grev. 



Grev. in Jlicr. Journ. VII, p. m. pi. VI, figs. 10—11. A. Schm. Nords. Diat. 



pi. I, f. 4.-1: 1,1. II, figs. l(i, 18. 



Frequent: Stamsund c, Raftsund r. Stene r, Gaukværo + c. 



Distribution : Coasts of the North Sea. frequent. Greenland. 

 The Mediterranean. Black Sea. Red Sea. Cape of Good Hope. 

 Indian Ocean. Pacific Ocean. Florida. 



var. versicolor (Grcn.) Grin. 



Grcn. in V. H. Synops, jil. X, f. (i. Xiiricnhi r. Guvs, in A. Schm. Nords. 



Diat. pi. ir, f. 17. 



A very well marked variety. 



Rare: Stamsund. +• 



Dixfriliutiun: North Sea. The Mediterranean. Sumatra. 



Z. Sp. Alg. 



A^. pygmæa Kc 

 . Van Heurck S' 



p. 94. pi. 10. 



IV, 



A'', clavata Greg. 

 4H, jd. V. f. 17. A. Schm. Nords. Diat. pi. 



Characteristic form, though hardly specifically different from 

 .certain varieties of N. Ji/ra. 



Not unfrequent: Moskenstrommen r, Stamsund r, Svolvær r, 

 the Ostnesfioi'd r. Raftsund r +, Stene r. 



It is hardly possible to keep this species distinct from certain 

 varieties of the preceding species (cfr. Cl. 1. c. p. (w;). 



Very rare: Stamsund r, Stene r. 



Distribution: Brackish water: Coasts of the North Sea. ]>altic. 

 Arctic regions. America. 



Piiiiiiilaria Khkb. 

 a. Capitatæ Cl. Synops. Navio. Diat. II, p. 75, 



P. microstauron Ehbb. 



A. Schm. Atlas pi. 44, f. 16. 



Very rare: Raftsund, r. 



Distribution: Fresh water species. Arctic regions. Northern 

 Europe. North America. 



