128 p. T. CLEVK, SYNOPSIS OF THE NAVICULOID DIATOMS. 



8. A. aspera Petit (1877). — V. semilanceolate. L. 0,o57 to O.oss; B. 0,oi3 to 0,oi8 mm. 

 Ventral margin straight, somewhat gibbous in the middle. Central nodule strong. Dorsal side 

 with 16 striae in 0,oi mm. composed of distant (about 10 in 0,oi mm.) puncta, forming undulate, 

 longitudinal lines. Ventral side narrow, finely striate. Striae 22 to 23 in 0,oi mm — D. de I'ile 

 Campbell p. 19 PL IV f. 9. Icon. n. PI. Ill f. 22. A. undata Lbud. Fortm. D. de la Malaisie 

 p. 11 PI. II f. 1 (1892). 



Marine: Gulf of Naples (Deby Coll.)! N. Zealand (Petit). 



9. A. groenlandica Cl. N. Sp. — V. narrow, lunate, with subacute ends. L. 0,09; B. 0,oi6 

 mm. Ventral margin straight. Median line approximate to the ventral margin. Central nodule 

 not transversely dilated. Striae of the dorsal side 14 (at the ends 15 to 16) in 0,oi mm. composed 

 of puncta (12 in 0,oi mm.) forming slightly undulating, longitudinal rows. Ventral part with 23 

 striae in 0,oi mm. — PI. IV f. 1. 



Marine: Davis Strait! 



10. A. acuta Greg. (1857). — Frustule subquadrate. Divisions of the zone about 4 in 0,oi 

 mm. finely transversely striate; striae about 21 in 0,oi mm. V. lunate, with arcuate dorsal mar- 

 gin, straight ventral margin and apiculate ends. L. 0,089 to 0,i5; B. 0,03 mm. Central nodule 

 transversely dilated into a stauros. Striae on the dorsal side 12 to 14 in 0,oi mm., composed of 

 puncta, about 10 in 0,oi mm., forming undulating, longitudinal rows. Ventral side very narrow, 

 finely striate; striae about 26 in 0,oi mm. — D. of Clyde p. 524 PI. XIV f. 93. A. S. Atl. 

 XXVI f. 19, 20 (21, 22?). 



Marine: Greenland! Spitsbergen! Finmark! North Sea! Morocco! Mediterranean Sea! China! 

 Magellan's Strait! 



Var. neogena Pant. (1889). — L. 0,084 to 0,092; B. 0,oi8 to 0,02 mm. Striae 17,5 in 0,oi 

 mm. — Pant. II p. 35. 



Marine: Hungary, Bory fossil (Pant.). 



Var. arcuata A. S. (1875). — V. with recurved ends. L. 0,06 to 0,15; B. 0,oi2 to 0,028 mm. 

 Dorsal striae 9 to 12 in 0,oi mm., composed of distant puncta (about 7 in 0,oi mm.). Ventral 

 striae very close. — A. arcuata Atl. XXVI f. 27 to 29. 



Marine: Balearic Islands! Seychelles (Van Heurck Coll.)! Macassar Straits (Grove Coll.)! 

 Samoa (Atl.), Mazatlan (Atl.), Gulf of Mexico (Atl.). 



Var. Idbyrinthica Grun. (1880). — V. in L. 0,i to 0,i3. Dorsal striae 14 to 17 in 0,oi mm., 

 composed of distinct puncta (10 in 0,oi mm.) forming undulating lines. Ventral striae 26 in 0,oi 

 mm. — A. labyr. Grun. A. D. p. 25. Icon. n. PI. IV f. 23. 



Marine: Balearic Islands! 



In the Diatoms of Clyde Greg, has 1857 figured (p. 521 PI. XIII f. 87) a form, named 



A. nohilis, which seems to represent an entire frustule of A. acuta. 



11. A. micans A. S. (1875). — V. hyaline, with strongly arcuate dorsal margin and straight 

 ventral margin. Ends apiculate. L. 0,12; B. 0,028 mm. Median line approximate to the ventral 

 margin. Central nodule dilated into a stauros. Dorsal striae 14 in 0,oi mm., distinctly visible 

 near the median line, but on the valve broken up into small, scattered puncta, 4 to 5 in 0,oi mm. 

 Ventral side very narrow; its striae close, about 26 in 0,oi mm. — Atl. XXVI f. 18. Icon. n. 

 PI. IV f. 7—9. 



Marine: Campeachy Bay (Atl.), Macassar Straits (Grove Coll.)! 



12. A. decnssata Grun. (1867). — Frustule thin, elliptical with truncate ends, about twice 

 as long as broad. Zone with numerous divisions. V. lunate with acute ends. L. 0,05 to 0,17; 



B. 0,011 to 0,0 3 mm. Median line close to the ventral margin. Central nodule dilated into a 

 transverse stauros. Dorsal side with very oblique striae, about 17 in 0,oi mm., turned in opposite 

 directions from the stauros and crossed by undulating, narrow, transverse blank bands. Ventral 



