162 r. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



As Cymhella elegans Cramer has issued in Rabli. Alg. Eur. X:o 1441 (18(53) a sample con- 

 taining several Cymbelhe, as C. Oisfula, C. helrefica, C. deluatula, C. Imris, C. affuiis, C. lepto- 

 ceras, C. amphicephaJu and C. aspera. As no description or figure of C. elegans is given, it is 

 impossible to determine what form the name denotes. 



9. C. laevis Naegeli (1849). — V. strongly asymmetrical, semilanceolate, gradually tapering 

 from the middle to the ends. Dorsal margin areuate; ventral margin straight or slightlj' convex 

 in the middle. L. 0,02!) to 0,o35; B. 0,oo7 to 0,uo8 mm. Median line somewhat excentric and 

 slightly areuate. Axial area indistinct. Strite of the dorsal side 13 (middle) to 15 (ends) in 0,ui 

 mm., slightly radiate. Strife of the ventral side 1(5 (middle) to 17 (ends) in 0,oi mm. almost pa- 

 rallel and iinely piinctate. — Naeq. in Ktitz. Sp. Alg. p. 59. V. H. Syn. p. 62 Pl. III f. 7. 

 A. S. Atl. IX f. 35. 



Fresh" water: Norway (Dovre)! Sweden (Gellivaara to (Jrtofta in Skåne)! Finland (Lapland 

 to Karelen)! Seotland! Zlirich (Grun.), Tours du Rhöne! 



lU. C. pusilla (tRUN. (1875). — V. asymmetrical, narrow, semilanceolate, ^vith subacute ends 

 and areuate dorsal, straight or slightly convex ventral, margin. L. 0,23 to 0,04; B. (»,oo.t to 0,oo7d 

 mm. Median line straight, strongly excentric. Axial area very narrow, not, or slightly, dilated 

 around the central nodule. Strite 15 to 18 (middle) or 16 to 20 (ends) in 0,oi mm., radiate in 

 the middle, transverse at the ends. — Grun. in A. S. Atl. IX f. 36, 37. V. H. Syn. Pl. III f. 5. 



Brackish water: Sweden (Baltic: Gothland, Malmö)! Halle! Neusiedler See (Grun.), Caspian 

 Sea (Grun.), Normandy ! Belgium (V. H.), Bayonne (Atl.), Sardinia (Grun.), Mouth of Jenissey! 

 South Africa! Ecuador! 



11. 0. yarrensis A. S. (1881). — V. narrow, semilanceolate, acute. L. 0,o7-. to (),ii; B. 

 0,0 12 to 0,0 1.-) mm. Median line nearly central; its terminal fissures in the ends. Axial area 

 narrow, linear, dilated in the middle to an elongated central area. Stria; 11 in O.oi mm., somewhat 

 more distant in the middle, where they are radiate, parallel in the ends. — Encyon? yarreust- 

 A. S. Atl. LXXI f. 16. 



Slightly brackish water: Yarra-Yarra (Australia)! Tasmania! 



12. C. nipifola Grun. (1881). — V. .slightly asymmetrical, lanceolate. gradually tapering 

 from the middle to the subacute ends. L. 0,o2 7 to 0,034; B. 0,0045 to 0,oor.5 mm. Median line 

 almcst central, straight. Axial area narrow, not dilated in the middle. Dorsal stri.t 12 (middle) 

 to 15 (ends) in 0,oi mm. slightly radiate. Ventral stria- 16 in 0,oi mm. slightly radiate — 

 Grun. in A. S. Atl. LXXI f. 70, 71. 



Fresh water (moist rocks): Arctic America! Seotland (V. H. Types), Salzburg (Atl.). 

 This species is very nearly akin to C. Icevin and diÖers scarcely in anytliing except the 

 le.ss asymmetrical valves. 



13. C. Reiiihardtii Grun. (1875). — V. slightly a.symmetrical, elliptic-lancetdate. with 

 convex dorsal and ventral margins. Ends obtuse. L. 0, 03 to 0, 01;; B. 0,oos to 0,ui4 mm. Median 

 line nearly central, straight. Axial area narrow, gradually dilated to the middle, wiiere it ex- 

 pands to a moderately large central area. Strite 10 (middle) to 13 or 14 (ends) in 0,oi mm. The 

 median strite are more distant thau the rest and slightly radiate. Towards the ends the striae 

 become almost parallel. — A. S. Atl. IX f. 27. Cl. M. D. N:o 132. 



Fresh water: Norway (Romsdalen)! Steinitz Sea (Atl.). 



The above description is fi'om speoimens in Cl. M. D. 132, determined by Grunow as 

 C. Keinhardtii . 



14. C. leptoceros (Enii. 1S43?) Grun. — V. asymmetrical, lanceolate. with .slightly gibbous 

 ventral margin and obtuse, sometimes slightlj' attenuated ends. L. 0, 02 to 0,04; B. 0,uos to 0, 01 

 mm. Median line slightly areuate. Axial area linear, not dilated around the central nodule. 



