146 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



0,01 mm. almost parallel. — Ralfs Prich. Inf. p. 913. St. Amphioxys Greg. T. M. S. IV p. 48 

 PI. V f. 23 (1856). St. Gregorii Grun. A. D. p. 47 PL III f. 64 (1880). V. H. Syn. p. 68 Suppl. 

 PI. A. f. 4. 



Brackish water: Sea of Kara! North Sea (coasts of Sweden! Scotland! and Belgium V. H.)> 

 Black Sea (Sebastopol)! Caspian Sea (? Grun.), Atlantic coast of N. N. America (Cape May)! 



S. Gregorii differs from S. salina by its broad stauros. Probably a variety with more 

 lanceolate outline is S. pacifica Castr. (Chall. Voy. p. 23 PI. XX f. 9), which is too insufficiently 

 described for identification. 



A small form of S. Gregorii from the mouth of the Somme has been named by Grunow 

 (in CI. M. D. 247, 255) var. diminuta. 



7. S. perminuta Grun. (1881). — V. elliptical, with rounded ends. L. 0,oi3 to 0,025; 

 B. 0,00 5 to 0,0 7 mm. Stauros narrow, pervious. Striee 22 to 23 in O.oi mm. slightly radiate. — 

 Grun. in CI. D. fr. Gronl. Arg. p. 12 PI. XVI f. 9. 



Brackish water: South Africa (Grun.), Patagonia (Arroyo de Olivera)! 



8. S. perpusilla Grun. (1884). — V. lanceolate. L. 0,oi8 to 0,02; B. 0,oo38 mm. Stauros 

 narrow, pervious. Striae not seen. — Grun. Franz Josephs Land D. p. 105 (53) PI. I f. 50. 



Marine: Franz Josephs Land (Grun.). 



Var. oitusiuscula Grun. — V. shorter, with more obtuse ends. Grun. 1. c. f. 49. 



Marine: Franz Josephs Land (Grun.). 



9. S. desiderata Cl. (1880). — V. linear to lanceolate with broad, capitate ends. L. 0,05; 

 B. 0,016 mm. Terminal fissures of the median line hook-shaped and turned in contrary directions. 

 Stauros narrow, linear, reaching nearly to the margins. Strise 14 to 19 in 0,oi mm. slightly 

 radiate, especially at the ends, very finely punctate. — Cl. in A. D. p. 14 PI. Ill f. 58. 



Brackish and marine: Sea of Kara! Behrings Island! 



10. S. septentrionalis Grun. (1884). — V. linear-lanceolate. L. 0,024; B. 0,oo48 mm. 

 Stauros narrow, not reaching the margin. Strise 23 in 0,oi mm. transverse, in the middle sub- 

 radiate. Grun. Franz Joseps Land D. p. 105 (53) PL I f. 48. 



Marine: Franz Josephs Land (Grun.). 



11. S. kryophila Grun. (1884). — V. elliptic-lanceolate, with obtuse ends. L. 0,019; 

 B. 0,007 mm. Stauros narrower towards the margins. Strise in the middle 16, at the ends 20 in 

 0,01 mm. slightly radiate, distinctly punctate. — Grun. Franz Josephs Land D. p. 105 (53) PL I f. 47. 



Marine: Franz Josephs Land (Grun.). 



12. S, pachycephala Cl. (1879). — V. linear, gibbous in the middle, with broad, capitate 

 ends. L. 0,04 to 0,055; B. 0,oo7 to 0,oo9 mm. Median line with contrary and hook-shaped termi- 

 nal fissures. Stauros pervious. Strise about 29 in 0,oi mm. radiate. — Cl. M. D. N:o 197. N. R. 

 D. p. 15 PL III f. 43. 



Brackish water: South Africa! Tasmania! 



13. S. Schinzii Brun. (1891). — V. linear, somewhat gibbous in the middle and at the 

 broad, rounded ends. L. 0,i3 to 0,17; B. 0,oii to 0,i2 mm. Stauros pervious. Terminal fissures 

 turned in the same direction. Terminal nodules large. Axial area narrow, linear. Strise 19 to 

 20 in 0,01 mm. slightly divergent in the middle and slightly convergent at the ends, distinctly 

 punctate. Puncta 19 to 20 in 0,oi mm. arranged in irregular, longitudinal rows. — Brun. 

 D. esptees n. p. 38 PL XVI f. 1. 



Fresh water: South "West Africa (Brun Coll.)! 



This form is very distinct from all other known species. The narrow axial area is bordered 

 by conspicuous, thick silicious ribs. 



