21. Nnrieujn frigUla Grun. 



a. Cell in valvar view, showing the usual ehr'omatophores; ■'=°/i- Senjenhavet, "A 1899, 0—80 m. (sample preserved in formaline). 



b. Cell with chromatophores; larger form; ^^"/,. Harent's Sea 71° 48' n., 49" 38' e. (S/S Heimdal =Vo 1900; c— e from the 

 same locality). 



c. 2 cells of a small form, one in valvar view, with ciii'omatophores, the otlier in side view. ■'^" i. Valve 34 \i x 11 |).. 



d. Typical iV. frigkla Grun., ='=7i. The ti'ansversc striæ are only slightly oblique towards the ends, not by far so nuicli as 

 in the figure. The longitudinal lines are only put on a small part of the valve. 55 ii x 14 \i-. 



c. A large specimen, somewhat deformed by being ignited on cover-glass; ''^7i- 96 [j. x 15 \i.: 12 transverse striæ on 10 |j.; 



distinct longitudinal lines, nnich clpser. No distinct centi-al area, 

 f. A twisted chain, probably not belonging to N. frigkla, ^^Vi. The Skjerstad Fiord 11,^ '-/4 19(i0, 0— 180 m. Un account of 



the chromatophores it seems related to N. Vanhoffeni and is perhaps N. pelagica. 



22. N'. Vanhoffeni Gran. 



a. A chain with protoplasmatic contents; ■*°7i- Senjenhavet, ''A 1899. — 80 m. 



b. 2 cells of a ciiain. in tlie process of selv-dividing; ■'^"/i. Barents Sea 71" 48' n., 49" 38' e., ''V» 1900 (f, g froui tlie 

 same locality). 



c. d. Chains, after being ignited on cover-glass, ^^Vi- The central nodules smaller and more indistinct than in the figure d; 

 in c they have disappeared. The cell walls, also in e, should be much narr'ower. Malangen, 'V* 1899, — 3 m. 



e. Chain, ignited; "''Vi- Brettesnes, '-"A 1899. The central nodules smaller than in the figure; the division lines of the con- 

 necting zone very fine. 



f. 2 valves with intermediate complex connecting zone, somewhat deformed (a short time treated with sulphuric and nitric 

 acids, then ignited on cover-glass I; ''=7i- Length 38 i^, breadth 6 |j. (or a little more). In the middle something like a 

 narr'ow transverse stauros was indistinctly seen. It might, however, also be due to indistinct striæ (the striæ otherwise 

 being quite invisible). 



g. Like f. The valve boatshaped, somewhat higher in the middle tlian at the ends. Length 24 \i., breadtli i; ;).. (Jn one 

 valve the stauroslike figure in the middle is shown. 



h. A narrow valve; »°7,. Folstad, 74 1899. 0—3 m. 



i. Cell in optical transverse section, with chromatophore. Barent's Sea, "A 1900. 



23. N. 2)chtgica Cl. A chain, after being ignited on cover-glass; ^'^°/i. Length of the cells 17 n. Brettesnes, 74 1899. 



24. SUmroncis sq)teiitrio)udis Grun. Barent's Sea ^Vs 1900 (cfr. above). 



a. Valve; '■'■'"/ 1. To the left the striæ in the middle part of the valve are represented. 



b— g. Different valves; "''71 • On several of tliem tlie striæ. of the middle part are shown. Tliose towards tiic ends wei'e 



only seen with difficulty, 

 h. A chain with protoplasmatic contents; ''°7i- 



i. Another chain. In 3 of the cells the protoplasmatic contents are seen. 

 k. A chain, after being ignited on coverglass; "■"7i- The striæ towards the ends are not seen distinctly. On most of tlic 



cells only the more conspicuous median striæ are illustrated. All striæ much finer than in the figure. 



25. S. (h-ani .TøRft. n. sp. Barent's Sea, 'Vo 1900. 



a. A chain with protoplasmatic contents; *^7i- (Sample not well preserved). 



b. A chain, after being ignited on cover-glass ; """/i. Iktween the cells, a connecting zone \\ith vci'v lino division lines is seen. 

 2(). Aclmanthes sp., «"/j. The Salten Fiord II, V4 1900, 0— 50 m. 



a. Lower valve with 3 cells of a chain, ignited. The structui'o of tlie valve is badly reproduccil. The striation should be 

 more regular, and only slightly radiate towards the ends. 



b. Like a. The upper end nodule should not be distant from the end. The valve lies somewhat obliquely. 



c. A chain ignited. Only the striæ of one valve is seen in the fignie. The 3 left cells are lepresented in oplical section. 



