FRESH-WATER DIATOMS FROM ICELAND 17 



taria adsunt, et quidem 5 in parte dorsali, 7 in parte ventrali. No- 

 dulis terminalibus ab apicibus remotis. 



Laugarvatn (S.), A. F. 



Area: Eur. 



This Cymbella is decidedly Prudent's above mentioned variant of 

 C. Cist, but hardly identical with Cymb. Nordenskjoldi O. M. (O. M. Patag. 

 P. 25, Tab. I, fig. 18) which has a similar double set of puncta. 



Var. maculata Ktz. Cl. Syn. 1, 173. V. H. Trt., Tab. I, fig. 41. 



Gljufurholtsa (S.) B. P., Saelulaskr (S.W.) A. F., Stadarhraun (S.W.) A. F. 

 Area: Eur.. Am., Grl., Spb., Fz. J. 



Cymbella cuspidata Ktz. Cl. Syn. I, 160. V. H. Trt., Tab. I, fig. 23. 



23 samples (S. 5. S.W. 8, N. 3, E. 7). 

 Area: Ubiquist, Grl. 



*Cymbella cymbiformis (Ag.) Ktz. Cl. Syn. I, 172. V. H. Trt., Tab. I, 

 fig. 38. 



20 samples (S. 2, S.W. 9, N.I, E. 8). Hot springs: 2. 

 Area: Ubiquist. 



Cymbella dubia sp. nov.. Tab. nost. II, fig. 20. 



Long: 43 /<, lat: 6,4 /<. Str. 12,5 in 10 /<. 



Valva linear!, apicibus rotundatis. Raphe obliqua, area hyalina, 

 media in parte valvse unilateraliter in areolam rotundatam dilatata, 

 cincta. Striis per totam valvam radiantibus. 



Mjoanes (E.) B. P. 



By reason of the oblique raphe, the stria? radiating throughout and 

 the unilateral central area, I have considered it proper placing this form 

 as a Cymbella. 



Cymbella Ehrenbergi Ktz. Cl. Syn. I, 165. V. H. Trt., Tab. I, fig. 22 

 (greatest fig.). 



23 samples (S. 8, S.W. 6, N. 3, E. 6). 



Var. delecta A.S. Cl.Syn. 1. c. A.S. Atl., Tab. IX, fig. 17 (Cymb. del.). 



Myvatn (N.), B. P. 



Area: Eur., Am., Aust., Grl. 



Cymbella gracilis Rabh. Cl. Syn. I, 169. V. H. Trt., Tab. XXVIII, 

 fig. 791 bis b (Encyon. grac.) and 791 bis c (Enc. lunatum). 



79 samples (S. 4, S.W. 26, NW. 3, N. 14, E. 31, s. I. IX Hot springs: 2. 

 Area: Ubiquist, Grl. 



Cymbella helvetica Ktz. Cl. Syn. I, 174. V. H. Trt., Tab. I, fig. 43. 



57 samples (S. 11, SW. 22, N. 6, E. 17, s. 1. 1). Hot springs: 2. 

 Area: Eur., Grl. 



*Cymbella heteropleura Ehr. var. minor Cl. Cl. Syn. I, 167. A. S. 

 Atl., Tab. IX, fig. 52. 



41 samples (S. 4, S.W. 9, N.W. 2. N. 8, E. 17, s. I. 1). Hot springs: 2. 

 Area: Eur., As., Grl., Spb. 



The Botany of Iceland. Vol. II. 



