28 P. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



Var. clerasa Grun. (1880). — Strije crossed on each side by a more or less narrow lateral area. 

 L. 0,055 to 0,067; B. 0, 0145 to 0, 015 mm. Strite 8,5 or 12 (middle) to 10 or 14 (ends)inO,oi mm. 



— N. clerasa Grdn. A. 13. p. 39 Pl. II f. 46. N. träns. v. clerasa Cl. Vega p. 467 Pl. XXXVI f. 32. 



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



Forma minuta. — L. 0,035; B. 0,oi2 mm. Stritii 12 in 0, 01 mm. — • Cl. Vega p. 467 

 Pl. XXXVI f. 37. 



Marine: Cape DesclinefF! 



Forma gracilenta Grun. (1880). — V. narrower, with prolonged ends. L. 0,o6 5 to 0, 07 5; 

 B. 0,009 to 0,011 mm. Striaj 10,5 to 11 in 0,oi mm. — N. derasa var.? gracilenta Grun. A. D. p. 40. 



Marine: Sea of Kära (Grun.). 



Var. incudiformis Grun. (1883). — Axial area unilateral, irregular, linear. StriiP. 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 v. abbreviata Grun. A. D. p. 39 Pl. II f. 43. N. incudiformis Grun. 

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



Marine: Cape Wankarema! 



Var. erosa Cl. 1883. — Strise 7,5 to 10 in 0, 01 mm., crossed by several narrow, undulating, 

 longitndinal bands. — JSf. erosa Cl. Vega p. 468 Pl. XXXVI f. 28. 



Marine: Cape Wankarema! 



Var. asymmetrica Cl. (1883). — Axial area unilateral, irregularly linear. Striee 9,5 inO,oi 

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



Marine: Cape Wankarema! 



55. N. finmarchica Cl. a. Grun. (1880). — V. lanceolate, with obtuse ends. L. 0,03 to 

 0,042; B. 0,0115 to 0,013 mm. Central nodule transversely dilated to a short stauros. Strise 12 

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



— Stauroneis fi.nm. Cl. a. Grun. A. D. p. 47 Pl. III f. 63. 



Marine: Finmark! Bohuslän! 



It is difficuit 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 var. clerasa f. minuta, from which it differs by its stauros and 

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

 being similar. 



56. N. kariana Grun. (1880). — V. broadly lanceolate, slightly rostrate. L. O, oss toO,oy; 

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

 area small, orbicular. StritB 12,5 to 14 in 0, 01 mm., parallel, finely lineate; lineolse forming longi- 

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



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



Var. detersa Grun. (1883). — Stritii crossed by a more or less large lateral area. — Cl. 

 Vega p. 469 Pl. XXXVI f. 36. Franz Jos. Land D. p. 103 Pl. I i. 23, 24. 



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



Var. frigida Grun. (1880). — L. 0,o44 to 0,o7; B. 0,012 to 0,oi3 mm. StriiB 15 or 16 

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

 forming longitndinal striee, about 2i6 in 0, 01 mm. — A. B. p. 39. Franz Jos. Land L).-p. 103 

 Pl. I f. 25. 



Marine: Sea of Kära! Franz Josefs-Land! 



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

 B. 0,(iii'.i to 0,0 15 mm. Axial area indistinct. Central area very small, orbicular. StritB 9 to 12 

 in 0,01 mm., finely Hneate; lineohv. not forming longitndinal stria?. — Franz Jos. Land D. 

 ]). 10:'. Pl. 1 f. 27, 2«. ^V. kariana v. vurta Cl. Vega p. 470 Pl. XXXVII f. 40 (1883). 



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



