KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 121 



Var. borealis KtJTz (1844). — L. 0,oi3 to 0,o25 mm. Strise 21 to 24 in 0,oi mm. — A. bo- 

 realis KtJTZ Bac. p. 108 Pl. III f. 18. V. H. Syn. Pl. I f. 20. A. salina (i minor V. H. Syn. p. 57. 



Fresh oi' brackish water: Helgoland (Kiitz), Gulf of Bothnia! 



Var. fossilis Pant. (1889). — L. 0,o32 mm. Striaj 22,5 in 0,oi mm. — A. salina var. fossilis 

 Pant. II p. 39 Pl. III f. 47. 



Brackish water: Hungary, fossil (Pant.). 



Var. angularis V. H. (1880). — Frustule in L. 0,02 5 to 0,043; B. 0,oi to 0,oi5 mm. slightly 

 constricted in the middle. Strise 20 to 23 (18 according to Van Heurck) in 0,oi mm. Divisions 

 of the zone about 14 in 0, 01 mm., distinctly striate, — A. angularis V. H. Syn. p. 57 Pl. I f . 21. 

 A. angulosa var. lyrata V. H. Syn. f. 22. A. hyhrida Grun. V. H. Syn. p. 57 V. H. T. Nio 12. 

 A. hullosa var. lineolata H. L. Smith T. N:o 611. 



Marine: England! Belgium! 



Var. himgarica Cl. — V. in length 0,044; B. 0,oi. Ventral margin straight. Strise 20 in 

 0,01 mm. — A. acutiuscula var. fossilis Pant. II p. 35 Pl. II f. 29. 



Brackish water: Hungary, fossil (Pant.). 



Var. protracta Pant. (1889). — L. of V. 0,08; B. 0,oo7 mm. Ventral margin couvex. Ends 

 protracted, capitate. Strise distinctly punctate 17,5 to 19 in 0, 01 mm. — A. protracta Pant. II 

 p. 39 Pl. I f. 5. 



Brackish water: Hungary, fossil (Pant.). 



12. A. acutiuscula Kutz (1844). — Frustule elliptic-lanceolate, with subrostrate and trun- 

 cate ends. L. 0, 035 to 0,(17; B. 0, 019 mm. Zone with numerous divisions, about 11 in 0, 01 mm., 

 transversely striate; strise 18 to 20 in 0,oi mm. V. narrow, 10 to 12 times as long as broad, 

 with subcapitate ends and straight ventral margin. Median line close to the ventral margin. 

 Strise 13 to 18 in 0,oi mm. finely, but distinctly punctate. — Bac. p. 108 Pl. V f. 32. V. H. 

 Syn. p. 57 Pl. I f 18. A. lineata Greg. Diat. of Clyde p. 512 Pl. XII f. 70 (1857) A. S. Atl. 

 XXVI f 59. A. coffceiformis var. Salinarum Grdn. Foss. D. Österr. Ung. p. 148 (1882). A. striata 

 Pant. II p. 39 Pl. II f 31 (1889)? A. striolata Pant. II p. 39 Pl. II f. 25 (1889)? A. juvenalis 

 Pant. III Pl. XIII f. 199 (1893). 



Brackish and marine: Greenland! Spitsbergen! Finmark! Sea of Kära! Baltic! North Sea! 

 Morocco! Balearic Islands! Caspian Sea (Grun.), Hiingary, fossil Czekehaza! Cape May! Samoa! 



Var.? subconstricta Grxin. (1878). — Frustule slightly constricted in the middle. L. 0,o35 

 to 0,045; B. 0,011 to 0,012 mm. Strise 15 to 17 in 0, 01 mm., on the zone fine. — Casp. Sea Alg. 

 p. 8 Pl. III f. 5. 



Brackish water: Caspian Sea (Grun.), N. Wales. 



Var.? constricta Grun. (1878). — Larger than the var. subconstricta. Strise 12 to 14 in 

 0,01 mm. — Casp. Sea Alg. p. 8. 



Marine: Tahiti, Tonga Islands, Samoa (Grun.), Seychelles (Van Heurck Coll. !) 



A. acutiuscula differs from A. coffeeiformis in its larger size, coarser strise, and distinctly 

 striate zone, but all these characteristies are variable, and in fact both species are connected by 

 intermediate forms, as is also the case with A. macilenta Greg. 



Pantocsek has described under the name A. Loczyi (II p. 37 Pl. V f. 93) a form that seems 

 to belong to A. acutiuscula, but the description does not agree with the figure, as the strise are 

 according to the description 11 in 0,oi mm. and on the fig. 14 to 15 in 0, 01 mm. The variety 

 subconstricta may be identical with A. angularis and the var. constricta with A. binodis. 



13. A. macilenta Greg. (1857). — Frustule in outline lanceolate, with truncate ends. 

 L. 0,037 to 0,12 mm. Zone with numerous divisions, 7 to 8 in 0, 01 mm., transversely striate; 

 strise 11 to 15 in 0, 01 mm. V. semilanceolate with rostrate-capitate ends. Median line close to 

 the ventral margin. Strise 9 to 12 in 0,oi mm., obscurely punctate. 



K. Sv. Vet. Akad. Handl. Band 27. N:o 3. 16 



