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



6. T. approximata Cl. N. Sp. — V. narrow, lanceolate, with acute ends, very convex. L. 0,2 

 to 0,3; B. 0,034 mm. Central area indistinct. Wing unilateral, close to the median line. Trans- 

 verse strise 19, longitudinal about 30 in 0,oi mm. — Pl. III f. 20, 21. 



Marine: Rembang Bay (Deby CoU.)! Macassar Straits (Grrove CoIL)! Colon (Deby Coll.)! 



7. T. adriatica Cl. N. Sp. — Frnstule nari'ow, linear, .slightlj' con.stricted in the middle. 

 L. 0,18; B.''0,025 mm. Wings indistinct. V. narrow lanceolate. L. 0,2; B. 0,oi8mm. Central area 

 small, transverse, narrowed towards the margin. Transverse strise 15 to 16, longitudinal 27 in 

 0,0 1 ram. — Pl. III f. 22, 33. 



Marine: Adriatic! 



8. T. maxima Greg. (1857). — Frnstule strongly constricted in the middle. L. 0, 13 to 0, 17; 

 B. 0,04 to 0,07, at the constriction 0,022 mm. Wings very distinct, projecting beyond the central 

 nodnle. V. lanceolate, acute. L. 0,22 to 0,24; B. 0,o32 to 0,o33 mm. Wing unilateral. Central 

 area distinct, narrow, transversely lanceolate. Transverse strise 15, longitudinal 21 in 0, 01 mm., a 

 little more distant outside the wing. — Amphiprora maxima GtREG. D. of Clyde p. 507, Pl. XII 

 f. 61. V. H. Syn. p. 120 Pl. XXII f. 4, 5. Grun. A. D. p. 65. 



Marine: North Sea! Mediterranean Sea! Adriatic! Java! Macassar Straits (Grove Coll.)! 



Var. subalata Cl. — L. 0, 1.5 mm. Wing not projecting beyond the central nodule. Trans- 

 verse strise 19 in 0, 01 mm., more distinct in the middle, punctate; puncta formiiig undulating, 

 longitudinal rows, about 16 in 0,oi mm. 



Marine: Macassar Straits (Grove CoU.)! 



Var.? clecussata Cl. — V. in L. O, le; B. 0,024 mm. Transverse strise 15 in 0, 01 mm., punctate; 

 puncta forming fine decussating lines, about 19 in 0, 01 mm. — Pl. III f. 24, 25. 



Marine: Seyshelles (Van Heurck CoU.)! 



Var. duhia Cl. a. Grun. (1880). — L. 0,072 to 0,09; B. 0,012 to 0,oi3 mm. Central area 

 rounded. Transverse strite 17 to 18 in 0,oi mm. — Amphipr. maxima var. duhia A. D. p. 65. 

 Pl. V f. 89. 



Marine: Finmark! 



It seems to be generally considered that there are wings on both sides of the median line, 

 but so far as I have seen, on examining a number of specimens, there is a wing only on one of the 

 sides. The wings of one frnstule are diagonal. The following insufficiently described and figured 

 species seem to be akin to T. maxima: Amphiprora ohlonga Grev. (T. M. S. XI p. 20, Pl. I f. 15, 

 1863), Amphipr. eximia Grev. (Edinb. N. Ph. J. XVIII p. 36 f. 13, 1863), Amphipr. Wendtii WiTT 

 (J. Mus. Godeffr. H. I p. 69 Pl. VIII f. 3, 1873). 



9. T. siimbavensis Cl. N. Sp. — V. lanceolate, gibbous in the middle. L. 0,i5; B. 0,03 mm. 

 Central area unilateral, (juadrate. AVing unilateral, very distinct. Transverse strise 19 in 0,oi mm. 

 Longitudinal strise very åne. 



Marine: Sumbava (Kinker CoU.)! 



This form is evidently nearly akin to T. maxima. 



10. T. gibbenila Grun. (1882). — Frnstule rectangular, with rounded angles, constricted in 

 the middle. L. O, o 7 to 0,09; B. 0,oi7 mm. Wing slightl}^ projecting outside the central nodnle. 

 V. narrow, lanceolate, with subcapitate ends, intequilateral, the broadest side having a gibbosity 

 in the middle. B. 0,02 mm. Strise. 16 in 0, 01 mm. finelv punctate. — Plat/iotropis gihherula Grvi^. 

 in Cl. M. D. N:o 309. V. H. Syn. Pl. XXII bis f. 12, 13. 



Marine: Firth of Tay! China (Deby CoU.)! 



11. T. pusilla Greg. (1857). — Frnstule rectangular, with rounded angles, scarcely constricted 

 in the middle. L. 0,055; B. 0,012 mm. V. narrow, lanceolate, unilaterally gibbous. Central area 

 indistinct. Strise 15 in 0,oi mm. — Amj^hipr. pusilla Greg. D. of Clyde p. 504 Pl. XII f. 56. 



Marine: North Sea (Coasts of Scotland! Belgium!) 



