TJSGA-EXPEDITIONENS VETENSKAPLIGA ARBETEN. 



469 



convex valve 9 in the middle, 10 in 0,o] ram. toward the ends, 

 reaching almost to the median line ; on the concave valve 8 — 

 10, on one side of the valve not reaching the median line, 

 on the other reaching the median line, but interrupted by a 

 linear area. 



Length 0,06 mm. Breadth 0,02 mm. — PI. 36, fig. 23. 



Cape Wankarema. 



var. elliptica CI. Valve elliptic. Striee parallel, 10 in 0,oi 

 mm. Length 0,o65 mm. 'Breadth 0,02 mm. — PI. 36, fig. 24. — 

 Cape Wankarema. 



The concave valve of this variety is scarcely different 

 from N. incudiformis Grun. 



N. (Bhoikoneis) obtusa CI. N. Sp. (Rhoic. obtusa CI. in CI. 

 & Moll. Diat. 315 — 318) Elongated, linear, with rounded obtuse 

 ends. Striae curved, not parallel, very faintly lineate, on one 

 half of the valve reaching the median line, on the other end- 

 ing at some distance, irregularly interrupted, 11 in 0,oi mm. 

 Length 0,075 mm. Breadth 0,oi4 mm. — PI. 36. fig. 25. — Cape 

 Wankarema. 



N. (Bhoikoneis) BoUeana Grun. (Verb. 1863, pag. 147, PI. 

 XIII, fig. 11) Greeul., Spitsb., Finm., Kara (Matotschkin), Cape 

 Wankarema. 



Specimens from Greenland have 8 radiant strise in 0,oi 

 mm. in the middle, 12 near the ends. Specimens from Wan- 

 karema are less arcuate, have in 0,oi mm. 10 striee, which are 

 almost parallel. The strise are transversely finely lineate as in all 

 species of the directa-group. Mr. Grunow has named this variety 

 from Wankarema Rh. BoUeana var. ? Siherica (CI. & Moll. Diat. 

 No 302.) — PI. 37, fig. 38. — Another variety from Cape Wanka- 

 rema has asymmetric striation and 11 strise in 0,oi mm. var. 

 asyminetrica CI. length 0,o45 mm. breadth 0,o] mm. PI. 37, fig. 39. 



N. kariana Grun. (A. Diat. pag. 39, PL II, fig. 44) Kara, 

 F. J. L., Cape Wankarema. 



a- genuina Strite 12 — 14 in 0,oi mm. Length 0,085 mm. 

 Breadth 0,026 mm. — Kara, F. J. L., Cape Wankarema. 



/3. detersa Grun. Mpt. Strise interrupted on both sides of 

 the median line by more or less broad areas. Length 0,09 

 mm. Breadth 0,o24 mm. — Kara, F. J. L., Cape Wankarema. 

 — PI. 36, fig. 36. 



r. minor Grun. (A. D. pag. 5. N. frigida Grun. A. D-. pag. 

 39). Strise 16 — 18 in 0,oi mm. Length 0,o44 — 0,o7 mm. Breadth 

 0,012 — 0,013 mm. — Kara, F. J. L. 



