KONGL. SV. VET. AKADEMIENS IIANDLINGAR. BAND 26. N:(» 2. 49 



Axial and central areas indistinrt 39. 



38. ■{ — area narrow, central area distinct 40. 



and central areas united to a lanceolate space 44. 



„ j Striae 12 to 13 in 0,oi mm C. fahitensis Grun. 



" \ — 20 to 21 — C. virginea Cl. 



.,, j Central area large 41. 



\ — — small 42. 



... j Elliptical, obtuse C. brevis Gb.v.o. 



I Lanceolate, acute C. Duseni Ch. 



■t, j Terminal fissures in contrary directions C. abnortnis Grun. 



^ \ — — the same ■ — 43. 



j L. 0,025 mm C. ladogensis Cl. 



I L. 0,0:5 mm C. Hnlstii Cl. 



. , j Longitudinal lines marginal or inframarginal 4r). 



( — — median 4G. 



.^ J Breadth 0,oo9 mm C. Lagerheimii Cl. 



' \ — 0,0 2 to 0,0.3 ram C. lathi fscuJa KtJTZ. 



.„ ( Longitudinal lines single C. amphisbcenn Bory. 



' \ — — double or triple 47. 



,^ ( Stris i» to 10 in 0,oi mm 48. 



47. < 



I — 12 — — C. bivittata Pant. 



.jj j Longitudinal double-lines approximate • C. permagna Bail. 



\ — — distant C. madagascarensis Cl. 



.f j Striffi very fine, 28 in 0,oi mm C. lepidula Grun. 



' distinct • . . 50. 



51. 



55. 



. ., I Axial area narrow, central area rounded C. Liber var. 



ol. ' 



\ — and central areas united to a linear or lanceolate space 52. 



Valve with broad ends 53. 



narrowed towards the ends 54. 



„ j L. 0,0,5 to 0,06 mm. . . • C. obtusa W. Sm. 



1 L. 0,108 mm C. Kainitzii Pant. 



I Stria 7 or 8 in 0,oi mm C. sectilis A. S. 

 — 10 to 12 — C. sanioensis Grun. 

 — 20 — — C. alpestris Grun. 



^r j Longitudinal lines fine 56. 



I — — broad 65. 



Axial area indistinct 57. 



Axial and central areas united in a linear or lanceolate space 64. 



I Central area small or indistinct 58. 



\ — — orbicular C. Anderssoni Cl. 



Stris 8 to 10 in 0,oi mm 59. 



— 11 to 20 — 61. 



^„ I Longitudinal lines double C. probabilis A. S. 



single 60. 



.„ j StrisB parallel C. robusta Grun. 



^ . I Central area with longitudinal marks or rows of puncta 

 ' ' 1 — — without — — — 



52. [ 



■*it 



58. i 



StrisB 



slightly radiate C. Eugenia Cl. 



. ( Valve gibbous in the middle and at the ends C. Silicula Ehb. 



1 — with parallel margins 62. 



_„ j Freshwater species C. bacillaris Greg. 



■ 1 Marine — 63. ') 



..., ( Longitudinal lines median C. Liber W. Sm. 



I — — marginal C. Spathula Brun. 



„, j Longitudinal lines median C. formosa Greg. 



\ — — inframarginal C. Frater Cl. 



') In this division C? elongnfnla Pant, may probably also be included. 

 K. Vet. Akad. Hand!. Hiind 26. N:o 2. 



