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 Coll.)! Macassar Straits (Grove Coll.)! Colon (Deby Coll.)! 



7. T. adriatica Cl. N. Sp. — Frustule narrow, linear, slightly constricted 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 

 0,01 mm. — PI. Ill f. 22, 33. 



Marine: Adriatic! 



8. T. maxima Greg. (1857). — Frustule 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 

 nodule. V. lanceolate, acute. L. 0,22 to 0,24; B. 0,032 to 0,o33 mm. Wing unilateral. Central 

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

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

 f. 61. V. H. Syn. p. 120 PI. XXII f. 4, 5. Gbtjn. A. D. p. 65. 



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



Var. subalata Cl. — L. O,!.-) mm. Wing not projecting beyond the central nodule. Trans- 

 verse striae 19 in 0,oi mm., more distinct in the middle, punctate; puncta forming undulating, 

 longitudinal rows, about 16 in 0,oi mm. 



Marine: Macassar Straits (Grove Coll.)! 



Var.? decussata Cl. — V. in L. 0,i6; B. 0,024 mm. Transverse strise 15 in 0,oi mm., punctate; 

 puncta forming fine decussating lines, about 19 in 0,oi mm. — PI. Ill f. 24, 25. 



Marine: Seyshelles (Van Heurck Coll.)! 



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

 rounded. Transverse strise 17 to 18 in 0,oi mm. — AmpMpr. maxima var. dubia A. D. p. 65. 

 PI. V f. 89. 



Marine: Fin mark! 



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 frustule are diagonal. The following insufficiently described and figured 

 species seem to be akin to T. maxima: Amphiprora oblonga Grev. (T. M. S. XI p. 20, PI. 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 PI. Vni f. 3, 1873). 



9. T. sumlbavensis Cl. N. Sp. — V. lanceolate, gibbous in the middle. L. 0,15; B. 0,03 mm. 

 Central area unilateral, quadrate. Wing unilateral, very distinct. Transverse strise 19 in 0,oi mm. 

 Longitudinal strise very fine. 



Marine: Sumbava (Kinker Coll.)! 



This form is evidently nearlj'^ akin to T. maxima. 



10. T. gibberiila Grun. (1882). — Frustule rectangular, with rounded angles, constricted in 

 the middle. L. 0,o7 to 0,09; B. 0,oi7 mm. Wing slightly projecting outside the central nodule. 

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

 in the middle. B. 0,02 mm. Strise 16 in 0,oi mm. finely punctate. — Plagiotropis gibberula GuvN 

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



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



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

 in the middle. L. 0,05.5; B. 0,012 mm. V. narrow, lanceolate, unilaterally gibbous. Central area 

 indistinct. Strise 15 in 0,oi mm. — Amphipr. pusilla Greg. D. of Clyde p. 504 PI. XII f. 56. 



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



