KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 123 



Var. Umbata Cl. — Frustule in L. 0,o5 to 0,o8; B. 0,o3 to 0,05 mm. Striae of the zone 

 10 to 11 in 0,01 mm. V. in L. 0,o9; B. 0,oi.5 mm. Striae 7 in 0,oi mm. Dorsal side with a 

 narrow hyaline limbus. 



Marine: Indian Ocean (Deby Coll.)! China (Deby Coll.)! 



18. A. exigua G-reg. (1857). — Frustule linear-lanceolate, with rostrate, truncate ends. 

 L. 0,025 to 0,04; B. 0,011 to 0,012 mm. Zone with about 8 divisions in 0, 01 mm. delicately striate; 

 strise 17 to 20 in 0,oi mm. V. with arcuate dorsal, straight ventral, margins and rostrate, capitate 

 ends. Strise 12 to 14 in 0,oi mm. not distinctly punctate. Median line close to the ventral 

 margin. — D. of Cl. p. 514 PI. XII f. 75. 



Brackish and marine: Scotland (Grreg.), Arctic America! Bessels Bay! Adriatic! Sandwich 

 Islands! Tahiti! West Indies! 



A. exigua is figured by GtBEGORY in a manner which admits of no trustworthy identification, 

 but as the striae are stated to be 11 in 0,oi mm. I believe that Gregory denotes this species, 

 which differs from smaller forms of A. acutiuscula in its smaller size, more delicately striate zone, 

 and not distinctly punctate striae. 



19. A. granulata Greg. (1857). — Frustule linear-lanceolate, with rostrate, truncate ends. 

 L. 0,038 to 0,04 (0,043 to 0,077 Grcg.) ; B. 0,oi3 to 0,018 (0,02 to 0,033 Greg.) in 0,oi mm. Zone 

 with 7 to 11 divisions in 0,oi mm., and longitudinal rows of large puncta, 10 to 13 in 0,oi mm. 

 V. with straight median line, closely approximate to the ventral margin. Striae 13 (10 to 14 Greg.) 

 in 0,01 mm. not distinctly punctate. — D. of Clyde p. 525 PI. XIV f. 96. 



Marine: Java! Macassar Straits! 



20. A. Jeschkei Jan. (1876). — Frustule about 3 times longer than broad, with triundulate 

 margins and broadly truncate ends. L. 0,04; B. 0,oi35 mm. Zone with about 4 longitudinal rows 

 of large puncta (about 11 in 0,oi mm.) in 0,oi mm. "Valve narrow with protracted and capitate, 

 incurved ends. Striae 12 in 0,oi mm. — A. S. Atl. XXXIX f. 14. 



Marine : ? 



21. A. turgida Greg. (1857). — Frustule in outline almost orbicular, with rostrate ends. 

 L. 0,025 to 0,035; B. O.ois to 0,02 mm. Zone with longitudinal divisions. V. in L. 0,02 to 0,o4; 

 B. 0,007 5 to 0,009 mm. with broad, arcuate dorsal margin, straight ventral margin and rostrate 

 ends. Median line close to the ventral margin. Striae 13 (9 Greg.) in 0,oi mm., not distinctly 

 punctate. - D. of Clyde p. 510 PI. XII f. 63. A. S. Atl. XXV f. 24, 25. 



Marine: Scotland (Greg.), Norway! Hed Sea! Java! Macassar Straits! Labuan! 



A. turgida is nearly akin to A. exigua, differing scarcely in anything but its greater breadth. 

 Grunows a. fluminensis (Verb. 1863 p. 12 PI. XIII f. 15) agrees in size and outline with A. turgida, 

 but has closer striae, 21 in 0,oi mm. The latter species is unknown to me. 



22. A. Grunowii A. S. (1874). — V. broad with straight ventral margin and elevated, 

 slightly triundulate dorsal margin. Ends capitulate. L. 0,054; B. 0,02i mm. Striae 10 in 0,oi mm. 

 composed of large, distant puncta. Median line closely approximate to the ventral margin. — 

 Atl. Probet. f. 15. 



Marine: Java (Atl.). 



23. A. corpulenta Cl. a. Grove (1891). — V. with almost straight ventral margin, very 

 elevated dorsal margin, and acuminate ends. L. 0,o96; B. 0,o45 mm. Median line close to the 

 ventral margin. Dorsal side with 6 striae in 0,oi mm. composed of distant puncta (4 to 5 in 0,oi 

 mm.). Ventral side very narrow, with about 8 striae in 0,oi mm. — Diatomiste I p. 68 PL X f. 14. 



Marine: Macassar Straits! 



