28 p. T. CLEVE, SYNOPSIS OF TIIK NAVICULOID DIATOMS." 



Var. (U-rusa GrRUN. (1880). — StricB crossed on each side by a more or less narrow lateral area. 

 L. 0,0.^5 to 0,067; B. 0,0145 to i),o\h mm. StritP 8,,^ or 12 (middle) to 10 or 14 (ends) in 0,01 mm. 

 — N. dcrasa (Irun. A. D. p. 39 PI. II f. 46. .V. tram. r. chrasa Cl. Vega p. 467 PI. XXXVI f. 32. 



Marine: Sea of Kara! Cape Wankarema! Cape DeschnefF! 



Forma minuta. — L. 0,035; B. 0,012 mm. Strire V^ in 0,oi mm. — Cl. Vega p. 467 

 PI. XXXVI f. 37. ^ 



Marine: Cape Deschneff! 



Forma gracilenta GtRUN. (1880). — V. narrower, with prolonged ends. L. 0,o65 to 0,075; 

 B. 0,009 to 0,011 mm. StricC 10,5 to 11 in (»,oi mm. — X. dcrasa var.'^ gracileuta Grun. A. D. p. 40. 



Marine: Sea of Kara (Grnn.). 



Var. incudiformis (Iriin. (1883). — Axial area nnilateral, irregular, linear. Striie on the 

 side, opposite to the axial area, crossed by a more or less broad lateral area, usually uniting with 

 the central area. — N. incus r. ahhrcviata (Irun. A. D. p. 30 PI. II f. 43. N. incudiformis (tRUN. 

 in Cl. Vega p. 467 PI. XXXVI f. 26, 30. 



Marine: Cape Wankarema! 



Var. crosa Cl. 1883. — Stria^, 7,5 to 10 in 0,(ti mm., crossed by several narrow, undulating, 

 longitudinal bands. — JSf. erosa Cl. Vega p. 468 PI. XXXVI f. 28. 



Marine: Cape Wankarema! 



Var. asymmciricu Cl. (1883). — Axial area unilateral, irregularly linear. Stritc 9,5 iiiO.oi 

 mm. as in var. erosa. — N. asymmetrica Cl. Vega p. 468 PI. XXXVI f. 27. 



Marine: Cape Wankarema! 



55. N. flninarcliica Cl. a Grun. (1880). — V. lanceolate, with obtuse ends. L. 0,o3 to 

 0,042; B. 0,0115 to 0,01. J mm. Central nodule transversely dilated to a short stauros. Striae 12 

 to 14 in 0,0 1 mm., slightly radiate, apparently smooth, crossed by a narrow, arcuate lateral area. 



Stauroncis finm. Cl. a. Grun. A. D. p. 47 PI. Ill f. 63. 



Marine: Finmark! Bohuslan! 



It is difficult to find the proper place in the system for this little form. There is no 

 allied species in Stauroneis, nor any other naviculoid form, to which it seems to be related, with 

 the exception of N. transitans rar. derasa f. tniniita, from which it differs by its stauros and 

 apparently smooth strite. This form is neither a Mastogloia nor an Achnanthes, both valves 

 being similar. 



56. N. kariana Grun. (1880). — V. broadly lanceolate, slightly rostrate. L. 0,o85 to 0,09; 

 B. 0,024 to 0,026 mm. Median line with approximate central pores. Axial area indistinct; central 

 area small, orbicular. Striee 12,5 to 14 in 0,oi mm., parallel, finely lineate; lineolse forming longi- 

 tiidinal strife, about 27 in 0,oi mm. — A. D. p. 39 PL II f. 44. 



Marine: Frans Josefs Land! Sea of Kara! Cape Wankarema! 



Var. defer sa Grun. (1883). — Strict crossed by a more or less large lateral area. — Cl. 

 Vega p. 469 PI. XXXVI f. 36. Franz Jos. Land I), p. 103 PI. I f. 23, 24. 



Marine: Franz Josefs-Land (Grun.), Cape Wankarema! 



Var. frigida Grun. (1880). — L. 0,044 to 0,o7; B. 0,012 to 0,oi;i mm. StrifE 15 or 16 

 (middle) to 17 or 18 (ends) in 0,oi mm. very slightly radiate throughout, finely lineate; lineolee 

 forming longitudinal striae, aboixt 26 in 0,o 1 mm. — A. D. p. 39. Franz Jos. Land D. p. 103 

 PL I f. 25. 



Marine: Sea of Kara! Franz Josefs-Land! 



57. N. gelida Grun. (1884). — V. lanceolate, with slightly rostrate ends. L. 0,o;i to0,o65; 

 B. 0,009 to 0,0 15 mm. Axial area indistinct. Central area very small, orbicular. Striae 9 to 12 

 in 0,01 mm., finely lineate; lineolai not forming longitudinal striae. — Franz Jos. Land D. 

 p. 103 PI. I f. 27, 28. N. kariana v. curta Cl. Vega p. 470 PI. XXXVII f. 40 (1883). 



Marine: Davis Strait! Franz Josefs-Land (Grun.), Cape Wankarema! Cape Deschneff! 



