KONGL. SV. VET. AKADEMIENS HANDLINGAR. HAND 27. N:0 3. 15 



3. N. rhynchocephala Kutz (1844). — V. lanceolate, with protracted, usually subcapitate 

 ends. L. 0,o4 to 0,o6; B. 0,oi to 0,oi3 mm. Axial area indistinct. Central area orbicular. Strise 

 10 to 12 in 0.01 mm., in the middle radiate and more distant, convergent at the ends, coarsely 

 lineate. — Bac. PL XXX f. 35. W. Sm. B. D. PL XVI f. 132. Donk. B. D. p. 38 PL VI f. 4. 

 Grun. a. D. p. 33 PL II f. 33. V. H. Syn. p 84 PL VII f. 31. N. cryptoc. v. rhynchoc. Strosse 

 Kliecken PL I f. 3. 



Fresh or slightly brackish water: Finmarken! Sea of Kara! Grulf of Bothnia! Sweden! 

 Belgium (V. H.), Saxony! Cape Deschneff! Arctic America! Dakota! Illinois! South Africa! Au- 

 stralian Alps! 



Var. amphiceros Kutz (1844). — V. broader lanceolate. Ends not distinctly capitate. Striae 

 8 to 10 in 0,01 mm. — JV^. amph. KiJTZ. Bac. p. 95 PL III f. 39. A. S. Atl. XL VII f. 25, 26. 

 V. H. Syn. p. 84 PL VII f. 30. 



Brackish water: Gulf of Bothnia! England! Belgium (V. H.), Sandwich Islands! 



N. rhynchocephala and var. amphiceros pass into each other; the latter graduates into 

 iV. ovenacea and N. viridula, the former is closely connected with JSf. cryptocephala. 



4. N. avenacea BriSb. (1878), — V. lanceolate, with acute ends. L. 0,o4 to 0,o5; B. 0,oo8 

 to 0,01 mm. Axial area indistinct; central area orbicular, large. Striee 10 or 12 (middle) to 13 

 (ends) in 0,oi mm., finely lineate, radiate in the middle, slightly convergent in the ends. — Grun. 

 Caspian Sea Alg. IV f. 23. N. viridula v. av. V. H. Syn. p. 84 PL VII f. 27. Pinnul. silesiaca 

 Bleisch (according to Grun.). Schizon.enia Smithii (Ag.) V. H. Syn. p. 110 PL XV f. 33. 



Brackish water: Falaise (Breb.), England! Belgium (V. H.), Black Sea! Caspian Sea (Grun.), 

 East Cape! Tasmania! 



N- avenacea connects N. viridula with N. rhynchocephala. 



5. N. viridula Kutz (1844). — V. broadly lanceolate, with subrostrate, obtuse ends. L. 0,05 

 to 0,0 7; B. 0,01 to 0,015 mm. Axial area indistinct. Central area large, orbicular. Strise 10 in 

 0,01 mm., coarsely lineate, radiate and more distant in the middle, slightly convergent in the 

 ends. — Bac. p. 91 PL XXX f. 47. Grun. A. D. p. 33 PL II f. 35. V. H. Syn. p. 84 PL VII 

 f. 25. Schisonema Thwaitesii V. H. Syn. PL XV f. 38, 39. 



Fresh and slightly brackish water: Sweden! England! Belgium (V. H.), Finland! Salzburg! 

 Sandwich Islands! — Australian Alps! Murray River! — Arctic America! 



Var. slesvicensis Grun. (1880). — V. linear-lanceolate, with broad, rostrate ends. L. 0,o3 

 to 0,05; B. 0,009 to 0,011 mm. Strige 8 to 9 in 0,oi mm. — N. sles. Grun. in V. H. Syn. p. 84 

 PL VII f. 28, 29. N. virid. f. minor A. S. Atl. XL VII f. 48. V. H. Syn. p. 84 PL VII f. 26. 

 Pinnul. silesiaca Fresenius Senckenb. Abh. IV, PL IV f. 27. 



Brackish water: Finland! Holstein! Belgium (V. H.), Greenland! 



Var. ahhreviata Grun. Ms. — V. linear, with rostrate and subcapitate ends. L. 0,oi6 to 

 0,03; B. 0,005 5 to 0,007 mm. Central area small. Strife 16 to 17 in 0,oi mm. 



Brackish water: Gulf of Bothnia, Tornea! South Africa! Bengal! 



Var. rostellata Kutz (1844). — V. lanceolate, with attenuated, subrostrate ends. L. 0,04 to 

 0.065; B. 0,01 mm. Striae 10 to 11 in 0,oi mm. — N. rost. Kutz Bac. p. 95 PL III f. 65. A. S 

 AtL XL VII f. 27 to 30. N. rhynchoc. v. rost. Grun. A. D. p. 33. V. H. Syn. p. 84 PL VII f. 23, 24. 



Brackish water: England! Belgium (V. H.), Marseilles (AtL), East Cape! Japan! 



The variety rostellata is a transitional form between N. viridula and N. amphirhynchus var. 

 amphiceros. 



* 6. N. yiilpina KtJTZ (1844). — V. lanceolate, gradually tapering from the middle to the 

 obtuse ends. L. 0,09; B. 0,oi4 to 0,oi6 mm. Axial area very narrow; central area large, orbicular. 

 Striae 10 to 11 in 0,oi mm., radiate in the middle, convergent in the ends, coarsely lineate; lineolae 



