KONCL. SV, VKT. AKADEMIKNS II A N I)MN(i AR. |{AN1> 26. N:() 2. 



155 



This species is remarkable for its arcuate valves, but in its essential cluuacteristics seems 

 to be nearest allied to N. plivatu. 



4(i. N. suavis Cl. and Grove X. Sp. — V. elliptic-lanceolate, Hnt. L. (),ii.-, ; V>. 0,04 

 mm. Axial area very Jiarrow. Central area small, rounded. Median line ending clo.se at the 

 margin. StriiE IH in 0,oi mm. equidistant throughout, finely punctate; pun(!ta about 18 in 

 0,0 1 mm., somewhat coarser around tlie central nodule, forming undulating longitudinal rows. — 

 PI. Ill f. 81, 32. 



Marine: Oamaru, New Zealand, fossil (Grove Coll.)! 



47. N. pllcatiilsi Grun. Ms. — V. elliptic-lanceolate, with subacute ends, convex, with a 

 more or less distinct longitudinal depression on each side of the median line. L. 0,07.5 to 0,11.5; 

 B. 0,02 to 0,0 2 5 mm. Median line with approximate central pores and small terminal nodules at 

 the ends of the valve, flexuose. Areas indistinct. Stritu 15 to 19 in 0,oi mm. at the middle, 

 slightly divergent, and IH to 20 in 0,oi mm. at the ends, parallel, and finely, but distinctly 

 punctate. — PI. Ill f. 'li^. 



Marine: Gulf of Naples! Balearic Islands! Madagascar! Seychelles! Japan (Brun Coll.)! 

 This is a very characteristic species, remarkable for its undulating median line. 



48. N. iiielegans Gro\'e and Sturt (1887). — V. lanceolate, gradually tapering from the ■ 

 middle to the somewhat obtuse eiids, where are short transverse diaphragms. L. 0, is; B. 0,o;i mm. 

 Median line with elongated central nodule and small terminal nodules at the ends of the valve. 

 Terminal fissures indistinct. Areas indistinct. Stria^, lo in 0,oi mm. radiate at the ends, some- 

 times crossed on each side of the central nodule by a short and narrow lateral area, punctate; 

 puncta, about 15 in 0,oi mm., forming undulating longitiidirml rows. — Grove and Sturt Q. 

 M. CI. J. Ill p. 132 PI. X f. 6. Icon. n. PI. V t. 16. 



Marine: Oamaru, New Zealand, fossil! 



This species is a very characteristic form, remarkable for the diaphragms in the ends, as in 

 Pleurostauron. It bears some resemblance to N. Kappa of the same habitat. 



49. N. (Scoliopleura) tuniida Br^b. (1849). — N. lanceolate, gradually attenuated to the 

 subacute ends. L. 0,i to 0,i6; B. 0,025 mm. Median line slightly sigmoid. Axial area \ery 

 narrow; central area small, somewhat elongated. Striai 13 to 14 in 



0,01 mm., in the middle where a few frequently are shorter than 

 the others, more distant, slightly radiate (at the ends transverse) 

 finely punctate. Frustule in the zonal-view rectangular with rounded 

 angles. Connecting zone slightly obli(|ue, not complex. — Bri<;b. in 

 Kutz. Sp. Alg. p. 77. .Y. Jnmciii AV. 8m. B. D. I p. 49 PI. XVI 

 f. 134 (1853). ScoUoplcnra iumula V. H. Syn. p. 112 PI. XVII 

 f. 11. 13. Pant. Ill PI. XVII f. 245. 



Marine and brackish: Franz Josephs Land (Grun.), North 

 Sea! Sebastopol! Ceylon! Sydney! 



Var. adriatica Grun. (18()0). — V. 0,027; B. 0,oo8 mm. Me- 

 dian line strongly sigmoid. Stri;c 12 in 0,o 1 mm. — Sculioj)lcara 

 adriatica Grun. Verh. 1860 p. 554 PI. V f. 24. 



Marine: Adriatic (Grun.). 



I have seen a few living specimens of A. tniuida. They had 



along the zone two chromatophore-plates, with entire margins. Each 



plate contained a row of 6 large, orbicular pyrenoids. At the ends 



of the frustules a number of small granules in lively motion was . , ,, , 



.... " *^ '■ |iA. tnmida with cell-contents 500 



visible. times magnified. 



