KONOL. SV. VKT. AKADKMIENS IIANDLINGAK. HAND 27. N:() 3. 



id:) 



10. A. baccata Leud. Foktm. (1871)). — Linear, with broad, rounded ends. L. (),i; B. (),o^r, 

 mm. Lower V. with wide and irregular axial area. Central area large and iriegularly transverse. 

 Striaj 7 in O.oi mm. formed of large puncta, arranged in nndulating, longitudinal rows. — Staaro- 

 neis haccata Leud. D. de Ceylan p. .'^7 PL III t. 35. Achnaiithrs cnrvata Leud. 1. c. PI. 1 f. 5? 

 A. hacc. Icon. n. PI. Ill f. 3. 



Marine: Colombo, Ceylon (Le Tournenr Coll.)! 



11. A. groeillandica Cl. (1873). — Linear with rounded ends. L. 0,04 to 0,of;; B. 0,00.1 

 to 0,007 mm. Upper V. with narrow axial area and strong costate stria;, 4, .5 to 6 in 0,oi mm. 

 crossed by a longitudinal line. Lower V. with indistinct axial area. Central area a broad trans- 

 verse fascia. Central pores of the median line somewhat distant. Stria' 5 to (i in 0,oi mm. 

 slightly radiate, formed by 3 to 4 large, distant puncta. Frustule genuflexed. Connecting zone 

 with a row of puncta, (1 to 7 in 0,oi mm. Lower valve with rudimentary diaphragms. — Ach- 

 HdHthidinni. groenlandiciim Cl. A. D. p. 25 PI. IV f. 23. Acltnanthes (jr. Grun. A. D. p. 20. 

 Cl. Vega p. 460 PI. XXXV f. 3. 



Marine: Arctic America! Greenland! Spitsbergen! Finmark! Behrings Island! 



12. A. crenulata Grun. (1880). — Elliptical to elliptic-linear, obtiise, with crenulated 

 margin (2,.i to 3 undulations in 0,oi mm.). L. 0,034 to 0,o76; B. 0,oi.5 to 0,02 mm. Upper V. 

 with very excentric and narrow axial area. Strife parallel, 6 to 6,5 in 0,oi mm. coarsely punc- 

 tate; puncta H to 7 in 0,oi mm. Lower V. with narrow but distinct axial area. Central area a 

 transverse fascia. Strife 6 to 7 in 0,oi mm. slightly radiate throughout, pimctate; puncta 6 to 7 

 in 0,01 mm. - A. D. p. 20. Cl. Diatomiste I p. 50 PI. IX f. 3, 4. 



Fresh or brackish water: New Guinea! Samoa! Australia (Daintree River)! 



Achnanthes Bory S:t Vincent (1822). 



Outline linear to elliptical or lanceolate. Uj^per valve with central and narrow axial area, 

 without central nodule and median line. Lower valve with median line and stauroid central 

 nodule. Axial area narrow. Structure similar in both 

 valves: transverse costcC, alternating with double rows 

 of small puncta, arranged in decussating rows. Frus- 

 tule genuflexed, .stipitate. No annuhis. Connecting 

 zone transversely striate. The cell-contents of A. lon- 

 (jipes have a number of scattered, rounded or elongated 

 chromatophore-granules. 



Achiianthcti, limited as above, has a great resem- 

 blance to Achnanthidiiim, as regards the manner of 

 living and the form of the frustule and the valves, but 

 the structure is different. Of the affinities of Achnan- 

 thes little can be stated. The structure of A. javanica 

 and of A. bcngalcnsis, which, according to Grunow, have 

 longitudinal lines, has some resemblance to that of 



iScoliofropis and Goniphoneis. Mastofjloia (irccilln has a similar structure, but differs greatly in 

 other respects. There is also some resemblance to Mastoncis, the central nodule of which also 

 forms a stauros, although short. 



1. A. longipes C. Ag. (1832). — Linear-elliptical, with broad, rounded and frequently 

 cuneate ends, usually slightly constricted in the middle. L. 0,oo.5 to 0, ig; B. 0,012 to 0,02 7 mm. 

 Upper V. convex. Axial area a central, linear silicious rib. Costaj 7 to 8 in 0,oi mm. parallel. 



Achiiantlics lonyipcs with cell-contents: iJUO times 

 magnified. 



