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



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

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



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

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

 small areas. Central area small and orbicnlar. Strite 13 in 0, 01 mm. — C. {x^dl. var.?) curuiro- 

 tmida Br. and Temp. D. foss. dn Japon p. 32 Pl. VIII f. 6. A. S. Atl. CXCV f. 10 to 17? 

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



Marine: Japan, fossil (Brnn). 



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

 transversely dilated. — G. pelluc. var. sigmoidea (xRDN. JSTovara p. 13 Pl. I f. 8. C. parthenopoea 

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



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



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

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



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



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

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

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

 sigmoid median line and narrow axial area, not dilated in the middle. Strife 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. 0,05.', to 0,07; 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 annuhis. 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. 0,0-) to 

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

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

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

 alternately longer and shorter. — Cymhella flexella Kutz. Bac. p. 80 Pl. IV f. 14. Cocconeis 

 Thivaite.m W. Sm. B. D. I p. 21 Pl. III f. 33 (1853). Achnanthidium flexellum. Bréb. in Kiitz. 

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

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

 Reinsch (accord. to Grun.). 



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

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



19. C. ininuta Cl. (1891). — Elliptical with broad, rounded ends. L. 0,o2i to O.oag; 

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

 orbicnlar central area. Strite 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 

 Thwaiiesii var. [i arctica Lägst. Spitsb. D. p. 41 Pl. II f. 16 (1873). AchnantJiidiuni minutiim 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 (Lägst.), Finland (Äbo)! Sweden (Wenern)! 

 This form resembles greatly Nav. liotaeana var. oblongella. 



k 



