KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 179 



Marine: Seychelles! Madagascar! Mauritius! Nicobar Islands (Grun.), Singapore! Japan! 

 China! Sandwich Islands! Samoa! West Indies! Colon! 



Var. curvirotunda Temp, and Brun (1889). — L. 0,i to 0,12; B. 0,o9 to 0,io5 mm. Lower 

 V. with fine, slightly sigmoid median line, ending at some distance from the margin in lunate, 

 small areas. Central area small and orbicular. Strise 13 in 0,oi mm. — C. (pell, var.?) curviro- 

 tunda Br. and Temp. D. foss. du Japon p. 32 PL VIII f. 6. A. S. Atl. CXCV f. 10 to 17? 

 a composita A. S. Atl. CXCVI f. 4, 5? 



Marine: Japan, fossil (Brun). 



Var. sigmoidea Grun. (1867). — L. 0,025; B. 0,02 mm. Median line sigmoid; central area 

 transversely dilated. — G. pelluc. var. sigmoidea Grun. Novara p. 13 PI. I f. 8. C. parthenopoea 

 Pedic. Rab. Alg. Eur. N:o 2223 (1870). 



Marine: Naples! Red Sea! Tahiti (Grun.). 



Var. conspicua A. S. (1894). — Lower V. with a row of large puncta between the median 

 line and the margin. — C. consp. Atl. CXCVI, 27, 28. 



Marine: Kings Mill Island, Singapore, Samoa (Atl.). 



17. C. cyclophora Guun. (1879). — Broadly elliptical. L. 0,oi7 to 0,028; B. 0,oi to 0,oi8 

 mm. Upper V. with sigmoid lanceolate axial area, lunate lateral areas, and on one side of the 

 centre a large circular annulus. Strise 16 in 0,oi mm. of decussating puncta. Lower V. with 

 sigmoid median line and narrow axial area, not dilated in the middle. Strise 28 in 0,oi mm. 

 of small puncta, forming decussating lines. Close to the central nodule is a large, circular an- 

 nulus. — Cl. M. D. N:o 254. Grun. A. D. p. 16. V. H. Syn. XXX f. 24, 25. 



Marine: South Australia! 



Var. Challengeri Cl. — L. 0,055 to 0,o7; B. 0,04 to 0,o6 mm. Upper V. with scarcely 

 sigmoid, in the middle transversely dilated, axial area, on both sides of it a lunate lateral area, and 

 on one side of the middle a circular annulus. Strise 17 in 0,oi mm. coarsely punctate; puncta 13 

 in 0,01 mm. Lower V. with slightly sigmoid median line, and narrow axial area not dilated in 

 the centre. Strise 24 in 0,oi mm. punctate; puncta 16 in 0,oi mm. On one side of the central 

 nodule a circular annulus. 



Marine: Off Marion Island Challenger St. 145 (Comber Coll.)! 



18. C. flexella Kutz (1844). — Rhomboid-elliptical, with obtuse broad ends. L. 0,04 to 

 0,05; B. 0,02 mm. Upper V. with narrow sigmoid linear axial area not centrally dilated. 

 Strise radiate throughout 16 in 0,oi mm. Lower V. with sigmoid median line, narrow axial area, 

 small and elongated central area. Strise 17 in 0,oi mm. radiate throughout, punctate, in the middle 

 alternately longer and shorter. — Cymbella flexella Kutz. Bac. p. 80 PI. IV f. 14. Cocconeis 

 Thwaite.iii W. Sm. B. D. I p. 21 PI. Ill f. 33 (1853). Achnanthidium flexellum Br^b. in Klitz. 

 Sp. Alg. p. 54. Grun. A. D. p. 17. V. H. Syn. p. 128 PL XXVI f. 29 to 31. Navicula Semen 

 Ehb. partim. Navicula Macula Greg. T. M. S. IV p. 43 PL V f. 9? Achnanthidium naviculoides 

 Rbinsch (accord, to Grun.). 



Fresh water: Spitsbergen (Lagst.), Beeren Eiland (Lagst.), Arctic America! Sweden! Fin- 

 land! England! Belgium! Switzerland (Brun.). 



19. C. minuta Cl. (1891). — Elliptical with broad, rounded ends. L. 0,02i to 0,029; 

 B. 0,01 to 0,012 mm. Upper V. with narrow linear axial area, dilated in the middle to a large, 

 orbicular central area. Strise 20 in 0,oi mm., almost parallel. Lower V. without axial area. 

 Central area large, rounded. Strise radiate, 20 (middle) to 25 (ends) in 0,oi mm. — Cocconeis 

 Thwaitesii var. fi arctica Lagst. Spitsb. D. p. 41 PL II f. 16 (1873). Achnanthidium minutum Cl. 

 D. of Finl. p. 53 PL III f. 6, 7 (1891). N. dissimilis W. Sm. Ann. Mag. Nat. XIX p. 8 PL II 

 f. 6; 1857? 



Fresh water: Spitsbergen (Lagst.), Finland (Abo)! Sweden (Wenern)! 

 This form resembles greatly Nav. Botaeana var. dblongella. 



