KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 135 



J Strise distinctly pnnctate A. magellanica Pet. 



\ — not distinctly pnnctate 4. 



j Axial area 



. I Axial area distinct A. angusta Cl. 



not distinct 5. 



% 



j. j Median line straight A. cymhiformis Ci,. 



' ' \ — — slightly biareuate A. bituminosa Pant. 



1. A. angusta (Greg. 1857) Cl. — V. narrow, semilaiiceolate, acute or siibacute. L. 0,o4 to 

 0,13; B. 0,005 to 0,0 18 mm. Median line straight, parallel and approximate to tlie ventral margin. 

 Axial area distinct and frequently moderately broad on the dorsal .side, indistinct or small on 

 the ventral side. Striee 7 to 17 in 0, 01 mm., not distinctly pnnctate. Both the dorsal and the 

 ventral sides of the valve are striate. 



This species comprises a number of forms. 



Var. typica Cl. — B. of the frnstnle 0,oi. L. of the valve 0,05 to 0,055; B. 0,oo5 to 

 0,007 mm. Strife 17 to 18 in 0,oi mm. — A. angusta Greg. D. of Ctyde p. 510 Pl. XII f. 66. 



A. angusta var. gracilenta Grun. A. S. Atl. XXV f. 15. A. Eulenstemii var. fossilis Pant. 1889 II 

 p. 36' Pl. I f. 3, Pl. III f. 49. Cymbella marina Castr. Cliall. Exp. D. p. 31. Pl. XXVII f. 13? 



Marine: Scotland (Greg.), Spitsbergen! Sea of Kära! Quincy, Massachusetts! Czekehaza, 

 Hungary (fossil)! Jamaica (Grove Coll.). 



The figure of A. angusta in Diat. of the Clyde is not snfficient for Identification withont 

 original specimens, but as in the description is stated that it has 17 to 18 striiE in 0, 01 mm. I 

 think that A. angusta Greg. may denote this form. A. Eulensteinii var. fossilis is described as 

 having 20 to 22,5 strise in 0,oi mm. I found 18 only in specimens from Czekehaza. Cymhella 

 marina Castr. may be this or another form of A. angusta, it is impossible to decide which from 

 the figure and the description. 



Var. oblongella Grun. (1878). — Frustule in breadth 0,oo8 to 0,oi3. V. in L. 0,032 to0,068; 



B. 0,006 to 0,01 mm. Striee 14 to 15 in 0,oi mm. — A. ohlongella Grun. Casp. Sea D. p. 7 Pl. IV 

 f. 20. A. exigua Greg. D. of Clyde p. 514 Pl. IV f. 75? A. angusta var. arctica Grun. A. D. 

 p. 24 Pl. I f . 9 (1880). A. lanceolata var. minor Cl. Vega p. 462 (1883). 



Marine and brackish: Sweden (Bohuslän)! Firth of Tay! East cape! Behrings Island! Ba- 

 learic Islands! Caspian Sea (Grun.), Campeachy Bay! Pensacola! Honolulu! 



A. exigiia Greg. may be this form although the strirB are stated to be 11 in 0,oi mm., 

 but it is impossible to decide withont original specimens. 



Var. Eulensteinii Grun. (1875). — L. of tlie valve O, os to 0,121; B. 0,oi6 to 0, 02 mm. Strise 

 11 to 12 in 0,01 mm. somewhat closer on the ventral side, or about 14 in 0,oi mm. — A. Eulen- 

 steinii A. S. Atl. XXV f. 1 to 3; XL f. 35 to 37. 



Marine: China! Japan! Govans Bay; Raised March; Leton Bank (Atl.), Cape May! 



Var. diducta A. S. (1875). — V. gibbous in the middle. L. 0,082; B. 0,oi5 mm. Dorsal 

 strife 10 to 11 in 0,oi mm. — A. diä. A. S. Atl. XXV f. 13. A. cy inhelloides var. latior Grun. 

 Atl. XXV f. 8. 



Marine: Java, Japan (Atl.). 



Var. ventricosa Greg. (1857). — V. in L. 0,059 to 0,13; B. 0, 013 to 0,oi8 mm. Dorsal strise 

 8 to 9 in 0,01 mm., ventral somewhat clo.ser. — A. ventricosa Greg. D. of Clyde p. 511 Pl. XII 

 f. 68. A. lanceolata Cl. D. from Spitsb. p. 667 Pl. XXIII f. 2 (1864). Cymhella criophila Castr. 

 Chall. Exp. D. p. 21 Pl. XXVII f. 5 1886 (strise distinctly pnnctate)? Cymhella marina Pant. Ill 

 Pl. XIX f. 274? 



Marine: Greenland! Spitsbergen! Sea of Kära! Finmark! Coasts of Scotland, Norway and 

 Bohuslän! Adriatic! Bab el Mandeb! Monterey (Atl. XXV f. 6). 



The fig. in Diat. of the Clyde is insufficient for Identification, still I have little doubt that 

 Gregory denotes this form. An intermediate form between Vor. ventricosa et T7/r. Evlensteinii 

 is fiff. 5 Pl XXV in A. S Atl. 



