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



Fresli water: Swedeii (Mälaren, Westergötland, Småland)! Finland (Åbo)! Scotland (Greg.), 

 Ireland! New Zealand! 



Var. antiqua GrUN. — V. witli snbcapitate ends. L. 0, 032 to 0,033; B. 0,on8 mm. Strife 

 7 to 8 in 0,01 mm., finely punctate. — C. ahn. var. anf. Grun. Foss. D. Öster. Ung. p. 1-11 

 Pl. XXIX f. 31. 



Fresh water: Hungary, fossil (Grun.). 



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

 Central area a transverse fascia. Strite 8 to 9 in 0, 01 mm. — Cymh. abnormis rar. fos.siUs Pant. 

 III Pl. XVII f. 255. 



Fresh water: Hungary, fossil (Pant.). 



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

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

 can hardly exist any donbt that Gregory really meant tliis species. 



47. C. tumidula Grdn. (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 ajjproximate central pores. 

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

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

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

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



Fresh water: Eostoek, fossil! Oxford! Triest (Atl.), Paris, Marly (Cl. 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, 01 mm. Axial area narrow, slightly dilated on the dorsal 

 side aromid the central nodule. Strise 11 or 12 (middle and dorsal) to 15 (ventral) in 0, 01 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. turgidnla, C. affmis etc. As far I can 

 see, there is no other difference between C. tumidula and C. salinarum than the somewhat diiFerent 

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



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

 truncate ends. L. 0, 03 2 to 0,o5; B. 0, 01 to 0,oi5mm. Axial area very narrow. Striaj in the middle 

 on the dorsal side 9 to 10 in 0,oi mm. at the ends about 11 in 0, 01 mm. finely punctate, puncta 

 about 24 in 0, 01 mm. Åt the ventral side of the central nodule are two small 2)uncta, ending the 

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



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

 Argentina ! 



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

 tral nodule. 



49. C. alfinis 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 0,04; 

 B. 0,00 7 to 0,01 mm. Median line slightly arcuate, excentric. Axial area very narrow, not dilated 

 around the central nodule. Striaj 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 Pl. VI f. 15? W. Sm. B. 

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

 V. H. Types N:o 26. Cymh. truncata Greg. M. J. Ill p. 39 Pl. IV f. 3 (1855)? Cocconem.a narmm 

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

 Cymh. af/inis var. tumida Lägst. Spitsb. L. p. 43 Pl. II f. 19? 



