28 ERNST ØSTRUP 



medio uno in latere valvæ deficientibus ibique fasciam unilateralem 

 satis latam relinquentibus. 



Fljötsdalur (E.) B. P. 



When I place this form under Nav. lineolatæ, it is owing to the 

 striæ which, by great enlargement, assume the peculiar "woollen" ap- 

 pearance, indicating a finer structure. 



*Navicula radiosa Ktz. Cl. Syn. II, 17. V. H. Tri., Tab. Ill, fig. 112. 

 286 samples (S. 66, S.W. 77, N.W. 4, N. 38. E. 97, s. 1. 4). Hot 

 springs : 8. 



Area: Eur., Af.. As.. Am.. Grl.. B. E., Spb. 



*Navicula Reinhardti Grün. Cl. Syn. II, 20. V. H. Trt., Tab. III, 

 fig. 132. 



5 samples (S. 3, N. 1, E. 1). 

 Area: Eur., As., Am.. Grl.. B. E. 



Var. Yenisseyensis Grun. Cl. Syn. 1. c. Cl. & Gr. A. D., Tab. II, 

 fig. 30 (N. digitr. striolata). 

 Alftatjörn (E.) B. P. 

 Area: As. 



Navicula rhyncocephala Ktz. Cl. Syn. II, 15. V. H. Trt., Tab. Ill, 

 fig. 119. 



21 samples (S. 7, S.W. 10, N. 1. E. 2, s. 1. 1 . Hot spring: 1. 

 Area: Ubiquist, Grl., B. E. 



Var. amphiceros Ktz. Cl. Syn. 1. c. V. H. Trt. 1. c, fig. 120. 

 7 samples (S.W. 6, N. 1). 

 Area: Eur., Aust. 



Navicula Salinarum Grun. Cl. Syn. II, 19. V. H. Trt., Tab. Ill, 

 fig. 108. 



Apavatn (S.) A. F. Skeiöarärsammr (S.) St. 

 Area: Eur., Af.. Am., Spb. 



Navicula semifasciata sp. now, Tab. nost. Ill, fig. 41. 



Long: 27//, lat: 9/*, str. 12 in 10«, subtiliter punctatis. 



Valva rhomboidea, apicibus subcapitals. Raphe area hyalina 

 angustissima, mediam partem valvæ versus patescente, ibique in 

 fasciam latam unilateralem dilatata, cincta. Striis radiantibus, apices 

 versus convergentibus densioribusque. 



Krökur (S.) H. Js. 



Navicula spatiata sp. nov., Tab. nost. Ill, fig. 42. 



Long: 16//, lat: 8//, str. 14 in 10//, obscure punctatis. 



Valva elliptica. Raphe area angusta cincta. Striis medianis 

 valde spatiatis, cetera in parte valvæ radiantibus, apices versus 

 leniter curvatis. 



Apavatn (S.) A. F. 



