KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 175 



line, reaching to the margin, no areas and fine strise, radiate throngliont, about 25 in 0,oi mm. 

 Diat. of Finland p. 51 Pl. III f. 8 (9?) 



Fresb water: Sweden (Ryssby in Calniar Län, baltic fresbwater deposit from tbe Ancylns- 

 epoch), Åbo, Finland! 



5. C. dirupta Greg. (1857). — Broadly elliptical to almost orbicular. Upper V. witb 

 linear, usually sigmoid, axial area. Lower V. with more or less distinctly sigmoid median line 

 and tbe terminal fissures in contrary directions. Central nodnle transversely dilated to an oiit- 

 wardly narrowing fascia. 



Var. typica Cl. — L. 0, 026 to 0,06i; B. O.ois to 0, 05 mm. Upper V. witb linear not sig- 

 moid axial area. Strite about 17 in 0, 01 mm. punctate; puncta forming undnlate longitudinal 

 rows. Lower V. witb very sligbtly sigmoid median line. Central area transversely dilated to a 

 fascia not reacbing to tbe margin. Striee 20 in 0, 01 mm. — G. dirupta GtREG. D. of Clyde p. 491 

 Pl. IX f. 25. A. S. N. S. D. Pl. III f. 21. Y. H. Syn. p. 133 Pl. XXIX f. 13 to 15. C. diapJiana 

 W. Sm. b. D. p. 22 Pl. XXX f. 254 partim (1853)? C. delicata A. S. Atl. CXCVI, 24? Probably 

 also G. oceanica, G. limiata and G. fasciata Ehb. 



Marine: G-reenland! Nortb Sea! Mediterranean Sea! Cbina! Bebring's Island! Tabiti (Grun.), 

 Cape of Good Hope (Grun.), California! Galapagos Islands! Colon! 



Var. dubia Grun. (1867). — Smaller. Striee 22 0,oi mm. Central nodule rarely, terminal 

 nodiiles ne%'er, transversely dilated. — Novara p. 14. 



Marine: S:t Paul (Grun.). 



Var.? Beltmeyeri Jan. (1894). — L. 0,04; B. 0,027 mm. Upper V. witb lanceolate, not sig- 

 moid area. Strije 12 in 0, 01 mm. crossed by 4 to 8 blank bands. — A. S. Atl. CXCVI, 22, 23. 



Marine: Leton Bank (Atl.), Pensacola (Atl.)? 



Var. flcxella Jan. Rab. (1862). — L._ 0,02 to 0,0.3; B. 0,02 to 0,o3 mm. Upper V. witb 

 narrow, lanceolate axial area. Strife 20 in 0, 01 mm. crossed on eacb side of tbe area by about 4 

 linear, curved blank bands. Lower V. witb sigmoid median line, reacbing to tbe ends, and trans- 

 verse central area. Strise about 19 in 0, 01 mm. — G. fle.vella Jan. Rab. D. Honduras p. 7 Pl. I 

 f. 11. G. dir. var. flex. V. H. Syn. Pl. XXIX f. 16, 17. 



Marine: Mediterranean Sea! Adriatic! Honduras (Jan. Rab.). 



Var. antarctica Grun. (1881). — L. 0,042; B. 0,035 mm. Upper V. witb narrow, linear axial 

 area. Strite about 15 in 0,oi mm., punctate; puncta forming longitudinal rows, about 13 in 0,oi 

 rara. Lower V. witb nearly straigbt median line, ending at sonie distance from tbe margin in trans- 

 verse terminal areas, turned in contrary directions. Strise 11 in 0, 01 mm. distinctly punctate; 

 puncta forming irregularly undulating longitudinal rows, about 11 in O, ni mm. — V. H. Syn. 

 Pl. XXIX f. 18, 19. G. dir. var. major Grun. Novara p. 14? 



Marine: New Zealand (Grun.), Cbina! 



Var. califoriiica Ci,. — L. 0,o4.t to 0,07; B. 0, 03 to 0,o6 mm. Upper V. witb sligbtly sig- 

 moid, lanceolate axial area not dilated in tbe middle. Strise. 11 to 16 inO,ui mm. of lar ge, di.stant 

 puncta, forming iindulating, longitudinal rows, about 9 in 0, 01 mm. — A. S. Atl. CXCVI, 17, 18(?) 



Marine: California fossil at S:ta Martha and S:ta Monica (Deby Coll.)! Moron, Spain, fossil 

 (Grove Coll.)! 



A'"ar. decipiens Cl. (1873). — L. 0,o25 to 0,o6; B. 0,034 to 0, 04 mm. Upper valve witb sig- 

 moid axial area in tbe middle dilated to an orbicular space. Strise 16 to 20 in 0, 01 mm. punctate; 

 puncta (10 in 0,oi mm.) forming irregularly decussating rows (14 in 0, 01 mm.). Lower V. with 

 sigmoid median line reacbing nearly to the ends. Strise 11 to 12 in 0, 01 mm. punctate; puncta, 

 about 14 in 0, 01 mm., becoraing larger outwards. — G. decip. Cl. D. Aret. Sea p. 14 Pl. I f . 6 

 (Lower V.). C. arcticum Cl. 1. c. Pl. II f. 11 a (Upper V.). 



Marine: Arctic America! Greenland! Finmark! Bebring's Island! 



