KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 171 



Fresh water: Sweden (Malaren, Westergotland, Smaland)! Finland (Abo)! Scotland (Greg.), 

 Ireland! New Zealand! 



Var. antiqua Grun. — V. with subcapitate ends. L. 0,o32 to 0,033; B. 0,oo8 mm. Strife 

 7 to 8 in 0,01 mm., finely punctate. • — C. abn. var. ant. Grun. Foss. D. Oster. Ung. p. 141 

 PI. XXIX f. 31. 



Fresh water: Hungary, fossil (Grun.). 



Var.? fossilis Pant. (1893). — Linear with slightly rostrate ends. L. 0,05; B. 0,oi mm. 

 Central area a transverse fascia. Striee 8 to 9 in 0,oi mm. — Cymh. ahnormis var. fossilis Pant. 

 Ill PI. XVII f. 255. 



Fresh water: Hungary, fossil (Pant.). 



This little form is of interest as it has some resemblance to a Gomphonema, in its uni- 

 laterally dilated central area. The fig. given by Gregory is not as good as desirable, but there 

 can hardly exist any doubt that Gregory really meant this species. 



47. C. tumldula Grun. (1875). — V. asymmetrical, linear-lanceolate, with rostrate ends. 

 L. 0,033 to 0,035; B. 0,007 to 0,009 mm. Dorsal margin arcuate, ventral straight, or somewhat 

 gibbous in the middle. Median line somewhat excentric, straight, with approximate central pores. 

 Axial areas indistinct; central area indistinct or on the dorsal side only. Striae on the dorsal side 

 13 (middle) to 15 (ends) in 0,oi mm., on the ventral side 14 in 0,oi mm., slightly radiate 

 throughout, finely punctate. On the ventral side of the central nodule are two puncta at the ends 

 of the two median striae. — Grun. in A. S. Atl. IX f. 33. Y. H. T. N:o 27. 



Fresh water: Eostock, fossil! Oxford! Triest (Atl.), Paris, Marly (CI. M. D. 195)! 



Var. salinarum Grun. (1875). — V. asymmetrical, lanceolate, with subacute, not rostrate 

 ends. L. 0,027 to 0,04; B. 0,oo8 to 0,oi mm. Axial area narrow, slightly dilated on the dorsal 

 side around the central nodule. Striae 11 or 12 (middle and dorsal) to 15 (ventral) in 0,oi mm. — 

 C. salinarum Grun. A. S. Atl. IX f. 28. V. H. T. N:o 26. 



Brackish water: Bay of Finland (Dannf.), Saule (Atl.), Italy! 



C. tumidula seems to connect C. amphicephala with C. turgidula, C. af finis etc. As far I can 

 see, there is no other diiference between C. tumidula and C. salinarum than the somewhat diiferent 

 shape of the ends. The above descriptions are from original specimens in Van Heurck's Types. 



48. C, turgidula Grun. (1875). — V. asymmetrical with more or less rostrate, obtuse, or 

 truncate ends. L. 0,032 to 0,0 5; B. 0,oi to 0,oi5mm. Axial area very narrow. Striae in the middle 

 on the dorsal side 9 to 10 in 0,oi mm. at the ends about 11 in 0,oi mm. finely punctate, puncta 

 about 24 in 0,oi mm. At the ventral side of the central nodule are two small puncta, ending the 

 median striae. — Grun. A. S. Atl. IX f. 23 to 26. 



Fresh water: Bengal (Atl.), New Zealand! Niagara falls! Porto Rico! Ecuador, Chimborazo! 

 Argentina! 



G. turgidula is nearly related to C. afflnis, but is larger and has 2 puncta below the cen- 

 tral nodule. 



49. C. atfinis Kutz. (1844). — V. more or less broad, semielliptical to semilanceolate with 

 almost straight ventral margin and slightly rostrate, obtuse or subtruncate ends. L. 0,025 to 0,o4; 

 B. 0,007 to 0,01 mm. Median line slightly arcuate, excentric. Axial area very narrow, not dilated 

 around the central nodule. Striae 10 or 11 (dorsal side) to 12 (ventral side) in 0,oi mm. a little 

 closer at the ends, slightly radiate, finely punctate. On the ventral side of the central nodule is 

 a small isolated punctum ending the median stria. — Kutz Bac. p. 80 PI. VI f. 15? W. Sm. B. 

 D. I PI. XXX f. 250? A. S. Atl. IX f. 29, 38*; LXXI f. 28, 29. V. H. Syn. p. 62 PI. II f. 19. 

 V. H. Types N:o 26. Cymh. truncata Greg. M. J. Ill p. 39 PI. IV f. 3 (1855)? Cocconema nanum 

 Hantzsch Rab. A. E. N:o 1321 (1862). A. S. Atl. LXXI f. 27. Coccon. gibbum A. S. Atl. X f. 27. 

 Cymh. af finis var. tumida Lagst. Spitsb. D. p. 43 PL II f. 19? 



