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



17. G. Grovei Cl. (1891). — V. linear, sigmoid at the attenuated, obliquely rounded, ends. 

 L. 0,4 to 0,6; B. 0,03 to 0,06 mm. Central nodule obliquely elliptical. Median line central, scarcely 

 flexuose. T.S. : L.S. 7,3 in 0,oi mm. — Pleur. Groveii Per. p. 22 PL VIII f. 1. 



Brackish water: Java! Singapore! 



18. G. spectabile Gtrun. (1891). — V. sigmoid, linear, obtuse. L. 0,3 to 0,34; B. 0,04 mm. 

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

 Terminal areas large. T.S. : L.S. 17,3 in 0,oi mm. — Pleur. sped. Per. p. 21 PI. VII f. 14. 



Brackish water: Brazil! 



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

 those of Prustulia and Naviculse OrthostichEe. 



19. G. 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. strise somewhat radiate. T.S. : L.S. ^729 in O'Oi ^™- — Fleur. scalproides BiABU. Alg. Eur. 

 N:o 1101. GrRUN. A. D. p. 60. V. H. Syn. p. 119 PL XXI f. 1. P. Spencerii var. scalpr. 

 Per. Vin f. 31. 



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



Var. (Endosigma) eximia Thw., (1856). — V. linear, obliquely truncate. L. 0,o6 to 0,08; 

 B. 0,009 to 0,01 mm. Median line straight, somewhat excentric in the ends. T.S. : L.S. ^727' 'Vss 

 in 0,01 mm. Frustules enclosed in gelatinous tubes. — Colletonema exim. 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. 



Fresh water: Sweden (Gulf of Bothnia, Upsala)! England ("W. Sm.), Belgium (V. H.), Bengal! 



Var. ohliqua Grun. (1880). — V. linear, obliquely truncate. L. 0,o69; B. 0,oi45 mm. Central 

 area elongated, oblique. Median line straight, curved at the ends, central. T.S. : L.S. '-'Ui in 

 0,01 mm. — Fleur. oU. Grun. A. D. p. 56. Per. VII f. 34. 



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



20. G. Temperei Cl. (1893). — V. linear, with obliqely truncate and rounded ends. L. 0,i4; 

 B. 0,014 mm. Median line central, straight, curved only at the ends. Central nodule small, 

 elongated. T.S. : L.S. "/g^. — Diatomiste II p. 55 PL III f. 3. 



Brackish water: Connecticut! 



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



21. G. plagiostomum Grun. (1880). — V. linear, with obliquely rounded ends. L. 0,i 

 B. 0,013 mm. Median line central, slightly flexuose. Central nodule large, ^ongated and oblique. 

 Transv. and longit. striae equidistant, 18 to 19 in 0,oi mm. — Pleur. plag. Grun. A. D. p. 56. 

 Per. VII f. 33. 



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



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

 be the same as PI. WansbecMi Per. VII f. 25, 26, is probably only a variety of G. plagiostommn. 

 Specimens from Hudson River (Icon. nost. PL VI (Part II PL I) f. 5) differ from that form in their 

 somewhat larger size (L. 0,i4 to 0,i6; B. 0,oi6 to 0,oi8 mm. T.S. : L.S. '7i8' 'Vis in 0,oi mm.). 



22. G. balticum Ehb. (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. strife equidistant, 11 to 16 in 0,oi mm. Nav. 



haltica Ehb. Abh. 1830 p. 114 (accord, to Chase). Pleur. halticum W. Sm. B. D. I 66 p. XXII 

 f. 207. Jan. Rabh. Honduras D. PL III f. 3. V. H. Syn. p. 117 PL XX f. 1. Per. VII f. 19, 20. 

 P. Makron Johnst. M. J. VIII p. 15. 



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

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

 lantic coasts of XJ. States! 



