118 P. T. CLEVE, SYNOPSIS OF TIIK XAVICrLOllJ DIATOMS. 



17. O. Urovei Cl. (l.sill). — V. linear, sigmoid at tlip attenuated, ohlifinfly rouiided, ends. 

 L. 0,+ to 0,6; B. 0,03 to 0,06 mm. Central iiodule obliquely elliptical. Median line central, scarcely 

 flexuose. T.S. : L.S. Vis in 0,oi mm. — Fleiir. Grovcii Per. p. 22 Pl. VIII f. 1. 



Brackish water: Java! Singapore! 



18. G. spectabile Grun. (1891). — V. sigmoid, linear, obtu.se. L. 0,.3 to 0,34; B. 0,<j4 mm. 

 Median line central, sigmoid, enclosed between two siliceous strings. Central nodule small, elongated. 

 Terminal areas large. T.S. : L.S. "/--a i" 0,oi mm. — Vlciir. spccf. Per. p. 21 Pl. VII f. 14. 



Brackish water: Brazil! 



This isolated species is very interesting, as tlie central nodule and the median line recall 

 tliose of Frustulia and Naviculte Orthostichfe. 



19. Cr. scalproides Rabh. (1861). — V. slightly sigmoid, linear, with obliquely rounded 

 ends. L. 0,058 to 0,068; B. 0,oi mm. Median line straight. Central nodule elongated. Median 

 transv. strije somewhat radiate. T.S. : L.S. --/og in 0,oi mm. — Fleitr. scal2jr0ick.sB.ABU. Alg. Eur. 

 N:o 1101. Grun. å. D. p. 60. V. H. Syn. 'p. 119 Pl. XXI f. 1. P. Spencerii tar. scalpr. 

 Per. Vm f. 31. 



Fresh water: Germany! U. States, Kansas River! Cameroon. Africa! 



Var. {Endosigma) eximia Thw. (1856). — A^ linear, oblicjuely truncate. L. 0,o6 to 0,o8; 

 B. 0,009 to 0,01 mm. Median line straigbt, somewhat excentric in tbe ends. T.S. : L.S. -Vn;, '"/ng 

 in 0,01 mm. Frustules enclosed in gelatinous tubes. - CoUetoncma cxim. Thw. in W. Sm. B. D. 

 II p. 69 Pl. LVI f. 350. Pleur. exim. V. H. Syn. p. 119 Pl. XXI f. 2. Per. VIII f. 47. 



Eresh water: Sweden (Gnlf of Bothnia, Ilpsala)! England (W. Sm.), Belgium (V. H.), Bengal! 



Var. ohliqua Grun. (1880). — V. linear, obliquely truncate. L. 0,069; B. 0,oi45 mm. Central 

 area elongated, oblique. Median line straight, curved at the ends, central. T.S. : L.S. --.^^ in 

 0,01 mm. — Pleur. obl. Gkun. A. D. p. 56. Per. VII f. 34. 



Brackish water: Sierra Leone (Grun.), U. States! Savannah, Ga.! 



20. O. Temperei Cl. (1893). — V. linear. with obliqely truncate and rounded ends. L. 0,14; 

 B. 0,0 14 mm. Median line central, .straight, curved only at the ends. Central nodule small, 

 elongated. T.S. : L.S. -'Z.,,,. — Diatomiste II p. 55 Pl. III f. 3. 



Brackish water: Connecticut! 



This form has nearly the same outline as P. lalficitiii. but is smaller and has closer striation. 



21. G. plagiostomiim Grun. (1880). — V. linear, with obliquely rounded ends. L. O.i; 

 B. 0,0 13 mm. Median line central, slightlj' Hexuose. Central nodule large, elongated and oblique. 

 Transv. and longit. stritE equidistant, 18 to 19 in 0,o 1 mm. — Pleur. play. Grun. A. L). p. 56. 

 Per. VII f. 33. 



Marina: Seychelles (Grun.), Sierra Leone! Barbados! 



Pleur. sciotense Sulliv. (1854 Sillim. J. XXVII p. 251; Grun. A. I), p. 59), which seems to 

 be the same as Pl. Wan.sheclni Per. VII f. 25, 26, is probably only a variety of (t. plutikistumuiii. 

 Specimens from Hudson River (Icon. nost. Part II Pl. I f. 5) ditfer from that form in their some- 

 what lai'ger size (L. 0, 14 to 0,i6; B. O.oie to 0,oi8 mm. T.S. : L.S. '"'is. '** m in '••"i lum.). 



22. G. balticHin Eub. (1830). — V. linear. with obliquely truncate and obtuse ends. 

 L. 0,2 to 0,4; B. 0,024 to 0,040 mm. Median line slightly excentric and somewhat flexuose. Cen- 

 tral area small, oblique. Transv. and longit. stiiju e(]^uidistant. 11 to lii in 0, 01 mm. — Xac. 

 haltica EiiB. Abh. 1830 p. 114 (accord. to Chase). Pleur. bnltirum W . Sm. B. D. I 66 p. XXII 

 f. 207. Jan. Rabh. Honduras D. Pl. III f. 3. A". H. Svn. ]). 117 Pl. XX f. 1. Per. VII f. 19, 20. 

 P. Mah-on Johnst. j\1. J. VIII p. 15. 



Brackish and marine: Baltic! North Sea! Caspian Sea (Grun.). Medlterranean Sea! Adriatic! 

 Red Sea! Java! Sumatra! Sandwich Islands! Samoa! Magellans Strait! Brazil! AVest Indies! At- 

 lantic coasts of U. States! 



