FRESH-WATER DIATOMS FROM ICELAND 57 



Var. naviculacea Grün. De Ton. Syll. 652. V. H. Syn., Tab. 

 XLI, fig. 8. 



Grimsey (N.) O. D. 

 Area: Eur. 



Synedra radians (Ktz.) Grun. V. H.Trt. 312, Tab. X, fig. 423. 



7 samples (S. 3, S.W. 4, E. 1). 

 Area: Eur., As., Grl. 



Synedra rostrata Pant. Pant. Bal. S. 76, Tab. VIII, fig. 4. 

 12 samples (S. 2, S.W. 4, N. 7). Hot spring: 1. 

 Area: Eur. 



Hustedt claims in Sud. p. 46, that Syn. rostrata is to be considered 

 a sporangial form "aus dem Gebiet der Synedra Ulna". 



Synedra rumpens Ktz. var.? fragilaroides Grun. cnfr. De Ton. 680. 

 V. Syn. ; Tab. XL, fig. 12. 



38 samples S. 14, S.W. 14, N.W. 1, N. 4, E. 4, s. 1. 1). Hot springs: 3. 

 Area: Eur., Am. 



Var. islandica var. nov., Tab. nost. V, fig. 76. 



Long: 36 /<, lat: 3,2 //, str. 20 in 10 ft. 



Valva lineari, apices versus leniter attenuata. Striis media in 

 parte valvæ aream nudam relinquentibus. 



Hallormstaôr (E.) B. P. 



I have placed this small Synedra as a variant of S. rumpens, pos- 

 sibly to be placed nearest to S. rump, genuina (V. H. Syn., Tab. XL, fig. 

 14), owing to its close striation; for the same reason perhaps related 

 to S. (Vaucheriæ var.?) capitellata Grun. (V. H. Syn., Tab. XL, fig. 26). 



*Synedra Ulna (Nitzsch) Ehr. V. H.Trt. 310, Tab. X, fig. 409. 

 207 samples (S. 50, S.W. 50, N.W. 6, N. 32, E. 69). Hot springs: 11 

 Area: Eur., Af., As., Am., Grl. 



Var. amphirhynchus Ehr. V. H.Trt. 311, Tab. X, fig. 414. 

 Minni Laxâ (S.) A. F. 

 Area: Eur. 



Var. Danica Ktz. V. H. Trt. 1. c, Tab. c, lig. 415. 



148 samples (S. 33, S.W. 30, N. 18, E. 67). Hot springs: 7. 



Area: Eur., Af., Grl., B. E. 



In 60 samples (S. 12, S.W. 16, N.W. 1, N. 2, E. 25, s. 1. 4) and in 2 

 hot springs I have noted S. Ulna, which however could not be deter- 

 mined accurately, they being only present as fragments or lying on the 

 connecting zone. 



Var. longissima W. Sin. V. H. Tit. 310, Tab. c, fig. 412. 

 Laugaâ (S.) A. F., Krökur (S. i H. Js., Hornarfjörör (E.) St. 

 Area: Eur., Af. 



