Diatoms. 



■213 



Very rare: Stamsund r. 53 ;i Long. 



Distribution: West coast of Norway. Bohuslan (Sweden). 



e. Lyrata? Cl. 1. c. p. 52. 



N. prietexta Ehrb. 

 Ehris. 1840, Mikrogeolog. pi. 1!'. f. 28 (Piwnularia p.). Van Heurck Synops. p. 



!ii'. P l. IX, i'. 13. 



Not unfrequent: Moskenstrommen -{-. Stamsund r, Svolvser r. 

 Raftsund r, Stene r. 



Distribution: Coasts of the North Sea. The Mediterranean. 

 Red Sea. Indian Ocean. Pacific Ocean. Kerguelen. Cape Horn. 

 America. 



N. Henuedyi \Y . Sm. 

 W. sm. Brit. Diat. II. p. 93. A. Schm. Nords. Diat. pl. 1. I. II. 



Very variable. 



Frequent: Stamsund c, the Ostnesfiord r, Brettesnes — Skroven i. 

 Raftsund -f, Stene r +. 



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

 Mediterranean. Red Sea. Indian Ocean. Pacific Ocean. Atlantic 

 Ocean. 



var. cireiunsecta Grun: 



Grun. in A. Schm. Nords. Diat. p. 8!), pl I. ti^s. 36, 42 (N. potysticta var. v. I. 



Frequent: Stamsund -j-c, Raftsund r, Stene ■+-. 



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

 terranean. Red Sea. Indian Ocean. America. 



Besides, a tine variety from Stamsund, r. with short marginal 

 stria 1 between the main ones. 



N. spectahilis iireg. 

 Greg. Diat. of Clyde p. 481, pl. IX. f. 10. A. Schm. Atlas, pl. 3, figs. 20-21. 



Though usually easily recognizable, this species is scarcelj 

 distinct from all forms of the very variable A. lyra (cfr. Cl. 

 1. c. p. CO). 



Not unfrequent: Moskenstremmen r -}-. Stamsund r -4-, SvolvEerr, 

 Raftsund r, Stene r +. 



An analogous variety to that of X. Hennedyi, with more 

 numerous marginal stria', occurs i Stene. r). 



Distribution: Coasts of the North Sea. Greenland. The 

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

 Horn. 



JV. abrupta (Greg.) Donk. 



Donk. Brit. Diat. p. 13. pl. II. I. 0. A. Schm. Nords. Diat. pl. I, f. 37. N. lyra 



var. a. Greg. Diat. of civ 1 ,- p. 486, pl. IX. figs. 14. 14 b. 



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

 Ostnesfiord c, Raftsund r, Stene +, Gaukvsero -f-c. 



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

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



JV. clavata Greg. 

 Greg. Micr. Jouvn. IV, p. 46, pl. V, i. 17. A. Schm. Nords. Diat. pl. I, f. 33. 



Characteristic form, though hardly specifically different from 

 certain varieties of A. lyra. 



Not unfrequent: Moskenstrommen r, Stamsund r, Svolvser r. 

 the Ostnesfiord r. Raftsund r +. Stene r. 



Distribution: Coasts of the North Sea. The Mediterranean. 

 Red Sea. Indian Ocean. Pacific < >cean. East roast of America. 



JV. lyra Ehrb. 



Ehbb. Ann t. p. 131, pl. 1. I. I'. 9. Van Heorck Synops, p. 93, pl. 10, E. 1. 



A', lyra var. Ehreribcrgii Cl. 1. c. p. 63. 



Somewhat rare: Moskenstrommen r. Stamsund r -)-. Svolvser +, 

 the Ostnesfiord r. Stene r. 



Distribution: Coasts of the North Sea. The Mediterranean. 

 Red Sea. Indian Ocean. Pacific Ocean. America. 



var. elliptica A. Schm. 



A. si iim. Nords. Diat. pl. I. I'. 30. Van Heurck Synops. pl. 10, f. 2. 



Very frequent: Stamsund -| . Svolvser | . Raftsund -j-.i Bret- 

 tesnes— Skroven r. Stene c. Gaukvan'o -)-. 



Distribution: Coasts of the North Sea. The Mediterranean. 

 Red Sea. Indian Ocean. Philippines. 



var atlantica A. Schm. 

 A. Schm. Nords. Diat. pl. I, f. 34. 



Very characteristic. Recalls sometimes A r . abrupta, but always 

 easy to distinguish from that species. 



Rare: Stamsund r +. Moskenstrommen r. 

 Distribution: Coasts of the North Sea. 



JV. forcipata Grev. 



Grev. in Micr. Joum. VII, p. S3, pl. VI, figs, 10—11. A. Schm. Nords. Diat. 



pl. I. f. 45; pl. II, figs. 10. 18. 



Frequent: Stamsund e, Raftsund r. Stene r, Gaukvsero -f-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 (Grun.) Grun. 

 Grun. in V. H. Synops. pl. X, f. 6. Xiiriculii v. Grun. in A. Schm. Nords. 



Diat. pl. II. e. 17. 



A very well marked variety. 



Rare : Stamsund. +. 



Distribution: North Sea. The Mediterranean. Sumatra. 



JV. pygmaea Kutz. 

 Kutz. Sp. Alg. p. 77. Van Heurck Synops. p. 94. pl. 10, f. 7. 



It is hardly possible to keep this species distinct from certain 

 varieties of the preceding species (cfr. Ci,. 1. c. p. 66). 



Very rare: Stamsund r. Stene r. 



Distribution: Brackish water: Coasts of the North Sea. Baltic. 

 Arctic regions. America. 



l'iiinnlai'ia Ehrb. 

 a. Capitatse Cl. Synops. Navic. Diat. II, p. 75. 



/'. microstauron Eheb. 

 A. Schm. Atlas pi. 44, f. 10. 



Very rare: Raftsund. r. 



Distribution: Fresh water species. Arctic regions. Northern 

 Europe. North America. 



