FRESH-WATER DIATOMS FROM ICELAND 43 



Hypotheca: Striis media in parte valvæ deficientibus, ibique 

 fasciam latam relinquentibus. 



Epitheca: Uno in latere mediæ partis valvæ spatium hyalinum, 

 soleæ equinæ instar, adest. 



Egilstaöir (E.) B. P., Hornafjôrôr E. St. 



This small form is hardly identical with Hustedt's Ach. lane, ven- 

 tricosa (enfr. Hust. Sud. (>4, Tah. II. ßg. 321; it seems to me, it should 

 rather he placed close to Ach. lane, færoensis. 



Achnanthes Peragalli Brun & Hérib. Cl. Syn. II, 192. Øst. D. D.. 

 Tab. IV, tig. .s:>. 



Apavatn (S.) A. F., îlfjôlsvatn (S.) A. F. 

 Area: Enr. 



Achnanthes rhyncoeephala A. Cl. A. Cl. Fini., 43, Tab. IV, fig. 85. 

 Hnsavik (X.) B. P., Grimsâ (E.) B. P. 

 Area: Eur. 



Kalyptoraphideæ 



Eschatoraphideæ 



Surirella Turpin 1827. V. H. Tit., 368. 



Surlrella asymmetrica sp. now, Tab. nost. IV, tig. 63. 



Long: 40 /i, hü: 10 //. 



Val va elliptice-lanceolata, margine una recta, altera autem con- 

 vexa. Area apicali angusta. Canaliculis in margine recta omnino 14, 

 in margine convexa omnino 7. 



In a flowing off from Geysir (S.W.) A. F. 



*Surirella biseriata Bréb. V. II. Tit., 369, Tab. XII, fig. 575. 



34 samples ^S. G, S.W. 8. X.W. 1. X. 7. E. 12). Hot springs. 



Area: Eur., AI'., As, Am. 



Surirella Engleri (). M. f. angustior. Ü. M. Nyassa, 28, Tab. 1, tig. 5. 

 A. S. AU. CCXLV, tig. 14. 



Laugavatn S. B. P. Mööruvellir S.W.; B. P. 

 Area : Af. 



Surirella granulata Øst. var. elliptica var. now, Tab. nost. IV, fig. (54. 

 Long: 72/^, lat: 20//, canalic. 2,7 in 10 u. 



Valva elliptica, irregulariter punctata, area apicali angustissima. 

 Reykjavik (S.W.) C. H. 0. 



This form answers in every respect, except by the exterior contour, 

 to Sur. granulata Ost. in Ost. Koss. 91, Tab. II. lig. 17. 



