122 



Var. typica Cl. — Frnstule with narrow zone, 3 to 4 times longer than hroad. Strise on 

 the zone 15 to 17 in 0,oi mm. V. in L. 0,o37 to O.is; B. 0,oo7 to 0,oi5 mm. Strise 11 to 12 in 

 0,01 mm. — A. macilenta Greg. D. of Clyde p. 510 PL XII f. 65. 



Marine: Coasts of Sweden and Scotland! Baltjik, fossil! Labuan! Seychelles! Behring Island! 



Var. ergadensis Greg. (1857). — Frustule 3 to 4 times longer than broad, with narrow zone. 

 L. 0,06 to 0,089; B. 0,oi9 mm. Strise of the zone 15 in 0,oi mm. V. about 12 times longer than 

 broad; its strise 9 in 0,oi mm. — A. ergadensis Greg. D. of Clyde p. 512 PL XII f. 71. 



Marine: Scotland (Greg.), Balearic Islands! Baltjik foss.! Macassar Straits! 



A. macilenta and A. ergadensis are badly represented by Gregory, and their identification 

 from the figures is doubtful. From the description of the number of strise, it seems possible that 

 Gregory denotes these forms, which are nearly akin to A. acutiuscula and differ from that species 

 in coarser strise and larger size only. 



14. A. Eunotia Cl. (1873). — Frustule broad, with truncate ends. L. 0,o8 to 0,12; B. 0,o5 

 mm. Zone with numerous divisions, about 6 in 0,oi mm. distinctly striate; strise 11 in 0,oi mm. 

 V. semilanceolate, with slightly rostrate ends, about 6 times longer than broad. Median line close 

 to the ventral margin. Strise on the dorsal side 7,5 to 8 in 0,oi mm., distinctly punctate; puncta 

 about 10 in 0,oi mm. Ventral side not striate. — D. of Arctic Sea p. 21 PL III f. 17. Icon. n. 

 PL IV f. 2, 3. A. cymiifera Cl. Vega p. 462. A. cymb. var. A. S. Atl. XXV f. 35. 



Marine: Greenland! Spitsbergen! Bohuslan! Bab el Mandeb! Labuan! 



Var. gigantea Grun. — V. in L. 0,15; B. 0,oa6 mm. Strise 7 in 0,oi mm.; puncta 6 in 

 0,01 mm. Ventral side with marginal puncta, 10 in 0,oi mm. — A. cymiifera var. gigatitea GnvN. 

 in V. H. T. N:o 546. 



Marine: Baldjik, foss.! Sumbava (Kinker Coll.!). 



15. A. Clara A. S. (1875). — V. semilanceolate with straight ventral margin and rostrate 

 ends. L. 0,io to 0,i4; B. 0,023 to 0,028 mm. Median line straight, close to the ventral margin. 

 Strise 5 in 0,oi mm. composed of lai;ge puncta, 5 to 6 in 0,oi mm. — Atl. XXV f. 20. 



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



16. A. costata W. Sm. (1853). — Frustule in outline broadly lanceolate, with rostrate and 

 truncate ends. L. 0,045 to 0,08; B. 0,03 to 0,065 mm. Zone with about 3 divisions in 0,oi mm., 

 coarsely 'striate, strise 10 in 0,oi mm. V. lunate with somewhat concave ventral margin and 

 rostrate ends. Median line close to the ventral margin. Strise on the dorsal side 9 in 0,oi mm. 

 composed of large puncta, 7 in 0,oi mm. Ventral side very narrow, with 10 strise in 0,oi mm. 

 — B. D. I p. 20 PL XXX f. 253. Greg. D. of Clyde p. 527 PL XIV f. 99. H. L. Smith Lens 

 II p. 83. A. inflata Grdn. A. S. Atl. XXV f. 29 to 30 (1875). 



Marine: North Sea! Mediterranean Sea (Perag.), Adriatic! Sumatra (Deby Coll.)! New Haven 

 (H. L. Smith), Pensacola! Colon! Campeachy Bay! Porto Seguro! Galapagos Islands! 



A. monilifera Greg. (J), of Clyde p. 511 PL XII f. 69) is probably a frustule of A. costata 

 or Terroris in the state of division. The same may be the case with A. monilifera in A. S. Atl. 

 XXVI f. 32. 



17. A. Terroris Ehb. (1853). — Frustule lanceolate with rostrate -truncate ends. L. 0,045 

 to 0,07; B. 0,018 to 0,02 mm. Zone with about 5 divisions in O.oi mm. striate; strise 11 in 0,oi 

 mm. V. semilanceolate with rostrate-capitate ends. Strise 8 to 9 in 0,oi mm., not distinctly 

 punctate. — B. Ak. 1853. A. Erebi Ehb. M. G. PL XXXV A 23 f. 2 (1854). Cl. Vega p. 462. 

 A. cymiifera Greg. D. of Clyde p. 526 PL XIV f. 97 (1857). A. S. Atl. XXVI f. 33; XXXIX 

 f. 18; XXV f. 17 to 19, 33, 34, 36. A. Lightsmithiana O'Meara M. J. XIV PL VIII f. 8 (1874)? 



Marine: Arctic America! Greenland! Spitsbergen! Finmark! Sea of Kara! East Cape! North 

 Sea! Mediterranean Sea! Macassar Straits! Gulf of Mexico! 



