KONGL. SV. VET. AKADEMIBNS HANDLINGAR. BAND 26. N:0 2. 159 



„^ ( Axial area indistinct . G. gracilis Ehb. 



' \ — — distinct, linear . . . . C. yarrensis A. S. 



an I Valve snbclavate . . C. Beccarii Gbun. 



S3, i- 



r 



\ — not clavate . ... 23. 



\ Axial area broad ....€. aapera Ehb. 



narrow or indistinct 24. 



_ . f Ventral and dorsal margins parallel C. Botellus Lagst. 



'^*- \ - - - - not - 25. 



_, / Obtnse or truncate 26. 



\ Acute 31. 



„„ f Stria delicate C. delicatiila KUtz. 



\ — coarse . . . 27. 



„„ J Terminal Assures straight . . . C. helvetica Kutz. 



\ — — reflexed . . . .... ... 28. 



„ I Striae coarsely punctate . . . C. Cistula var. 



\ — finely punctate .... ... 29. 



„„ J L. about 0,04 mm . . 30 



r 



\ L. about 0,12 mm . . C. lanceolata Ehb. 



„. J Median line almost straight C. parva W. Sm. 



■ \ — — arcuate . . C. affinis Kutz. 



„^ f Median striae radiate . . . . . . C. pusilla Gbun. 



'^^- \ - -not - 32. 



„„ I Strongly asymmetrical . . . ... . . . C. IcBvis N.a;GELi. 



\ Slightly — . . . .... . . . C. rupicola Gnvns. 



(Ends capitate . . . ... ... 34. 

 — rostrate . .... . 37. 



— apiculate . . 46. 



— not protracted .... 47. 



„ . j Striae very fine 0. microcephala Geun. 



\ — distinct 35. 



Axial and central areas indistinct 36. 



35. p^^"' 



distinct C. naviculiformis Atteesw 



:al C. angustata W. Sm. 



decidedly asymmetrical ... C. amphicephala N.aiGELi. 



„_ y Median ventral striae ending with isolated puncta . C. tumidula Gbun. 



'*^- ■' - — not — - - 38. 



„„ / Central area small or indistinct . . . . . 39. 



' \ — — orbicular 45. 



„„ I L. 0,02 to 0,0 

 \ L. 0,07 mm. 



mm ... .40. 



or more . ■ 42. 



«.) 



j L. about 0,025 mm. ..... . . . . . C. obtusiuscula Gbun. 



\L. about 0,05 mm. ... 41. 



Median striae about 9 in 0,oi mm. .. ,., . . . . C. lata Gbun. 



— 12 — ■ . . . . C. spuria Cl. 



.„ I Valve stout 44. 



\ — narrow .,, 43. 



.„ /Striae 11 in 0,fli mm. . • ;, • ■ ^ '^^ ^^odderi Cl. 



I — 17 — — ..,.!..' C. amphioxys Gbun. 



r Ends broad . ... . . . . . C. Cucumis A. S. 



■ I _ not very broad C. Ehrenhergii Kutz. 



j Small C. hybrida Gbun. 



\ Large C. heteropleura Ehb. 



( Valve with undulated margins ... . ■ C. Schmidtii Gbun. ' 



I — _ non — — . . .... ..... C cuspidata KCtz. 



._ (Ends obtuse '.'.-. ... 48. 



*'• \ - acute 59. 



( Valve linear 49^ 



\ — lanceolate . . 51. 



C. conifera Br. and H^hib. 



