E. Jørgensen. 



var. Gregorii (Ealfs.) Geux. 



Gruk. in Cl. and Gkun. Aret. Diat. p. 37. Naviada Gregorii Ealfs in Pritch_ 



Inf. p. 901. A. SCHM. Nord.s. Diat. pl. II, f. 22. 



Very rare: Stamsund r, Gaukværo r. 

 Distribution: Coasts of the North .Sea. Baltic, 

 ons. Pacitic Ocean. Kerguelen. 



Arctic reai- 



N. nortlmiuhriea Donk. 

 DONK. Micr. Jouni. I, p. U, pi. I, f. 5, A. Scum. Atlas pi. 47, figs. 19—20. 



Very rare: Stamsund r, Stene r r. 

 DistrUiittioii : North Sea. 



N. zostereti Gron. (v) 

 Gkun. in Wien. Verb. ISOO p. h28, pi. IV, f. 23. A. Schm. Atlas pi. -17, f. 43. 



Rare: Stamsund r. Stene r, Gaukværo r. 

 Distribution: Tlie Mediterranean. Indian Ocean. Pacific 

 Ocean. Brazil. 



N. fortis (Greg.) Donk. 



Donk. Bi-it. Diat. p. 57, pi. 8, f. 8. Pinmdaria f. Greg. Micr. Journ. IV, 



p. 47. p). V, f. 19. A. Schm. Atlas pi. 46, figs. 37—39. 



Perhaps only a coarse variety of V". canceJhita. 

 Very rare: Stene, r. 



Distribution: North Sea. Arctic regions (Spitsbergen, Finmark, 

 Greenland). 



A^. rostellata (Greg.) A. Schm. 



A. Schm. Noi-ds. Diat., expl. ad pi. II (..N. rosfellaria Greg.;") Pinmdaria r. 



Greg. Diat. of Clyde p. 488, pi. IX, f. 20. 



Very rare : Stene, r. Probably the same species as the follow- 

 ing one. There does, however, really exist a form answering to 

 Geegoey's figure, without a central transverse area. 



Distribution : Coasts of the North Sea. 



A. Schm. Atlas pi. 4(j, 



N. crucitera Grun. 

 50—53: Nprds. Diat. pi. II, f. 31 /..rosfellaria G: 



Must be reckoned as a variety to the preceding species (or vice 

 versa). 



Very rare: Stamsund r; Gaukv;pro r. 



Distribution: Coasts of the North Sea. Baltic. The Medi- 

 terranean. Sumatra. 



N. distans (W. Sm.) Cl 

 Pimndaria d. W. Sm. Hi-it. Diat 



Very rare: Raftsund r, Stene i'. 

 Distribution: North Sea. Arctic regions. 



A. Schm. Ni 



N. compressicauda A. Scum. 

 Is. Diat. p. 91, pi. II, i. ;i5; Atlas 



The peculiar aspect of the ends of the valve is due to the 

 convexity. The valve is boatshapcd with sharp stems, at the bot- 

 tom of which the terminal nodules are situated. I'hus they are 

 rather distant from the very ends. 



Rare: Stam.sund r -(-. 



Distribution: Coasts of the North Sea. Morocco. The Me- 

 diterranean. 



N. siiperimposita A. Schm. 

 A. Schm. Nords. Diat. p. 90, pi. II, f. 34: Atlas pi. 46. t'. 61. 



In many respects answering to the preceding species, though 

 undoubtedly distinct. 



Very rare: Stamsund, r. Several specimens observed. 

 Distribution: West coast of Norway. Baltic. Morocco. China. 



N. opima Gruk. 



N. fortis var.? opima Qnws. Novara p. KO, pi. I A, f. 13. N. ojntiia A. Schm. 



Atlas pi. 46, figs. 24—26. 



Very rare: Stamsund, r. 



Distribution: West coast of Norway. Baltic. Arctic regions. 

 Barcelona. 



d. Lævistriatæ Cl. 1. c. p. 66. 



Radiate striæ, not distinctly punctate nor lineolate. Valve 

 more or less lanceolate. 



N. palpebralis Bréb. 



Bkéb. in W. Sm. Brit. Diat. I, p. .50, \A. 31, f. 273. Van Heurck Synops. 



p. 96, pl. 11, f. 9. 



Rare: Stamsund r +, Moskenstrømmen r, Gaukværø r. 

 Distribution: Coasts of the North Sea. The Mediteranean 

 East coast of North America. Davis' Strait. Galapagos Islands. | 



VH. Synopi 



var. Barclayana (Greg.) VH. 



11, f. 12. Xaricula B. Greg. Diat. of Clyde p. 480. 

 id. IX, f. 9. 



Rare: Stamsund, r. 



Distribution: Coasts of the North Sea. The Mediterranean. 



var. semiplena (Greg.) Cl. 

 Cl. 1. c. p. 70. Pinmdaria s. Greg. Jlicr. Journ. VII, 



84, pi. VI, f. 12. 



Rare: Stamsund, r. 



Distribution: Scotland. Finmark. Spitsbergen. 



var. angulosa (Greg.) VH. 



Van HerrcK Synops, pl. 11. t'. lU. Xaricula a. Greg. Micr. Journ. IV, p. 42, 



pi. V, i'. 8. A. Schmidt Noids. Diat. pi. II, f. 19. 



Rather frequent: Stamsund +. Stene r, Gaukværo r^-- 

 Distribution: Coasts of the North Sea and Western Europe. 

 The Mediterranean. 



var. minor liRi n. 

 Grun. in Cl. et Grun. Arct. Diat. p. 30, pi. I, f. 2: 

 Diat. of Clyde p. 477, pi. IX, f. 



Rare: Stamsund r, (Jaukva^ro r. 

 Distribution: J'^inmark. Belo'ium. 



N. præsecta A. Schm. 

 A. SciiM. Nords. Diat. pi. II, f. 20, 



Recalls the mr. souijilruu of the preceding species (cf. Cl. 

 1. c. p. 70), but has a much finer structure. Striæ 15 on 10 \i.. 

 An obscure line is to be seen between the central area and the 

 margin. Perhaps a species of Caloneis. 



