468 GLEVE, DIATOMS. 



pag. 39, PI. II, fig. 43) Stride 8 in 0,oi mm. on one half of tbo 

 valve more approximate to the median line than on the other, 

 and on this half interrupted. Length 0,o95 — 0,o5 mm. Valves 

 sometimes arcuate. 



Cape Wankarema. PI. 36, fig. 26, 30. 



This variety seems to connect Nav. (Bhoihoneis) snperha 

 CI. with N. transitans. 



N. Zostereti Grun. — More or less lanceolate. Stride slightly 

 radiant, distinctly tranversely lineate; strire 5 to 12 in 0,oi 

 mm., more approximate at the ends. 



forma genuina (A. Schm. Atl. PI. XL VII, fig. 42—44 with 

 about 7 striae in 0,oi mm.). Specimens from Kara have 9 striae 

 in 0,01 mm. Length 0,i mm. Breadth 0,02 mm. 



var. acutiuscnla Greg. (Pinn. acutiuscula Greg. T. M. Soe. 

 IV, pag. 48, PI. V, fig. 21) Striae about 11 in 0,oi mm. — Kara. 

 (Length 0,og mm. Br. 0,oi mm.) 



Nav. longa Greg. (1. c. fig. 18) with 5 str. in 0,oi, may per- 

 haps be regarded as a form of N. Zostereti, were not the median 

 line described as generally twisted, which character seems to 

 indicate that N. longa is a ScoliopJeura. 



N. erosa CI. — More or less elliptic, about 5 times longer 

 than broad, tapering regularly from the middle to the ends. 

 Striae coarse, 7 V2 — 10 in 0,oi mm., transversely finely lineate, 

 a little radiant, interrupted, so that they have the appearance 

 of being composed of fragments. Central nodule surrounded 

 by a small area. Length 0,i mm. Breadth 0,02 mm. — PL 36, 

 fig. 28. — Cape Wankarema. 



N. (Rhoikoneis) frigonocephala CI. N. Sp. — Linear with pa- 

 rallel sides and cuneate, sometimes protracted ends. Valves 

 often arcuate. Striae coarse 10 — 12 in 0,oi mm., almost paral- 

 lel, interrupted as in N. erosa, transversely lineate. Length 

 0,05 — 0,065 mm. Breadth 0,oi — 0,012 mm. — PI. 36, fig. 29. — Cape 

 Wankarema. 



N. asymmetrka CI. N. Sp. — Elongated elliptic, 4 — 5 times 

 longer than broad. Striae almost parallel, interrupted, 9 ^'2 in 

 0,01 mm., transversely lineate, on one half of the valve reaching 

 the median line, on the other ending at some distance from 

 it. Length 0,i mm. Breadth 0,02?. mm. — PL 36, fig. 27. — Cape 

 Wankarema. 



Perhaps an asymmetric variety af N. erosa. 



N. (Blioilwneis) snperha CI. A'alves rhombic, arcuate (or 

 sometimes straight), convex and concave valves being more or 

 'less different. • Striae almost parallel, transversely lineate, on the 



