Diatoms. 



205 



d. Dubiae Grun. 



N. littorea Grun. (?) 



Van Heurck Synops. pi. 59. f. i>\. V. thermalis v. littoralis Grot, in Cl. et 



Grot. Arct. Diat. p. 78. 



Very rare: Stamsund r. 11:5 ;>. long; 7 keel puneta on 10 |x. 

 Similar to X hybrida, but is longer and narrower, with more distant 

 keel puneta and more excentric keel. Also Stene, r r. 



Distribution: Newcastle. Lysekil (Sweden). 



e. Bilobattv Grun. 



N. bilobata W. Sm. 

 W. Sm. Brit. Diat. I. p. 42. pi. 15, f. 113. Van Heubck Synops. p. 175. 



pi. 60, t. 1. 



Very rare: Ostnesfiord. r. 



Distribution : Frequent on the coasts of Europe (the most north- 

 ern ones excepted). Pacific Ocean. 



N. hybrida Grun. 



Cf. above p. 103. 



Perhaps derived from the plankton. 

 Very rare: Stamsund r. 

 Distribution: Cf. above p. 103. 



A r . Mitchelliana Greenl. 



Cf. above p. 104. 



Very rare: 0stnestiord r, Stene r. 



Distribution : North America. Arctic regions. 



f. Jnsignes Grun. 



N. insignis Greg. 

 Greg. Micr. Journ. V, p. 80, pi. 1. f. 46. 



Not unfrequent: Stamsund r. Ostnesfiord r. Gaukvaero r, 



Stene r. 



Distribution : Coasts of Western and Northern Europe. Arctic 



regions. Adriatic Sea. Red Sea. 



var. notabilis Grot. 



Grun. in Cl. et Grin. Arct. Diat. p. S4. Van Heurck Synops. pi. 51, f. 5. 



Very rare: Gaukvsero r. 476 \i long; 9—10 striae on 10 \x. 

 Distribution: The Mediterranean. 



var. spathnlitera Grin. 

 Van Heueck Synops. pi. 61, f. 3. 



Very rare: Stamsund r. 



Distribution: The Mediterranean. West Indies. 



N. Smithii Kalfs. 

 Ralfs in Pritch. Inf. p. 781. Van Heurck Synops. pi. 61, f. 4. 



Not unfrequent: Stamsund -f, Stene r. 

 Distribution: Coasts of Western Europe. Adriatic Sea. Fin- 

 mark (var. marginifera Grun.). 



g. Spatlmlatx Grun. 



N. annularis \V. Sm. 

 \Y. Sm. Brit. Diat. 1. p. 1". pi. [3, f. 117. Van Hedrck Synops. p. 177. pi. 62, 



figs. 11-14. 



Rather frequent: Stamsund r. Svolvaer -+-, 0stnesfiord r, 

 Gaukvsero -4-. 



Distribution: Frequent on the western and northern coasts 

 of Europe. The Mediterranean. Arctic regions. Ceylon. Cape 

 Horn. 



N. spathulata B] i b 

 Breb. in W. sm. Brit. Diat. I. p. 10, pi. 31, i. 268. Van Heurck Synops. p. 177. 



pi. ii-'. figs. 7—8. 



Somewhat rare: Stamsund r, 0stnesfiord, Gaukvaero r. 

 Distribution: Frequent on the western and northern coasts of 

 Europe. The Mediterranean. Arctic regions. 



N. distans Greg. 



(inEG. Diat. of Clyde, p. 530. pi. XIV. f. 103. Van Heurck Synops. pi. 62, f. 10. 



Rare: Stamsund r (several specimens); Ostnesfiord r. 

 Distribution: Coasts of the North Sea. The Mediterranean. 



Red Sea. Australia. Baffin's Bay and Davis' Strait. Cape Wan- 

 karema (Cl., varieties). 



h. Sigmata Grot. 



N. sigina (Kutz.i W. Sm. 

 W. Sm. Brit. Diat. I. p. 39. pi. 13. f. 108. Synedra s. Kutz. Bacill. p. 67, 



pl. 30. f. 114. 



Frequent: Stamsund +. Svolvaer +• Ostnesfiord -f, Gauk- 

 vsero r +, Stene r. 



Distribution : Cosmopolitan. 



i. Lanccolatie Gbot. 



N. lanceolata W. Sm. 

 \V. Sm. Brit. Diat. I. p. 40. pl. XIV. f. 11*. Van Heurck Synops. p. 182, 



pl. 68, figs. 1—4. 



I have two times seen the wavy longitudinal lines, described 

 and illustrated bj W. Smith. They were more distinct than the 

 transverse striae. 



Very rare: Stamsund r. Gaukvaere r. Stene r. 



Distribution: Frequent on the coasts of Europe, the most 

 northern ones only excepted. Indian I >cean. 



k. Nitzehiella (Rabenh.i Grun. 

 N. longissima (Breb.) Ralfs. 



Cf. above p. 104. 



Very rare: Gaukvaero r. 



Distribution: Coasts of the North Sea and Western Europe. 

 The Mediterranean. West Indies. Indian Ocean. 



