60 ERNST ØSTRUP 



Fragilaria producta Lgst. Lgst. Spb. 15, Tab. I, fig. 1 (F. æqualis 

 prod.). 



41 samples (S. 6, S.W. 12, N.W. 2, N. 8, E. 13). 

 Area: B. E.. Spb. 



Fragilaria rhombica sp. nov., Tab. nost. V, fig. 80. 



Long: 16//, lat: lu, str. 10 in 10//. 



Valva rhomboidea, apices subcapitatos versus valde attenuata. 

 Striis mediam partem valvæ versus obliterantibus ibique areolam 

 centralem relinqventibus. 



Grimsey (N.) O. D. 



I think this small Fragilaria is probably to be considered as an 

 intermediate form between F. constr. venter and F. Harrisoni. 



Fragilaria Smithiana Grun. V. H. Syn., Tab. XLV, lig. 1. 

 Ulfjölsvatn (S.) A. F. 

 Area: Eur. 



Fragilaria triundulata sp. nov., Tab. nost. V, fig. 81. 



Long: 26 //, lat: 6,7 //, str. 16,6 in 10 //. 



Valva leniter triundulata, apicibus capitalis. Striis marginalibus, 

 aream apicalem lata m relinquentibus. 



Apavatn (S.) B. P. 



This form has nothing to do with Fr. construens var. triundulata 

 Beichelt (cnfr. Øst. Diat. Afl. 57, Tab. II, fig. 15). Possibly it is more 

 closely related to Frag, trigibba Pant. (Pant. Bal. S. 79, Tab. IX, fig. 224), 

 but it is scarcely identical with it. 



Fragilaria undata W. Sm. V. H. Trt. 324. A. S. Atl., Tab. CCXC, 

 figs. 48—61. 



5 samples (S.W. 2. N. 1, E. 2). 

 Area: Eur., Grl. 



In tab. nostr., tig. 82, I have given a figure of a particularly elegantly 

 built form of Frag, undata. It was found in a sample from West Ice- 

 land, St. 



*Fragilaria virescens Ralfs. V. H. Trt. 323, Tab. XI, fig. 442. 

 30 samples (S. 5, S.W. 15, N.W. 1, N. 5, E. 3, s. 1. 1). 

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



Var.? exigua Grun. V. H. Syn., Tab. XLIV, figs. 2— 3. 



6 samples (S. 2, X. 2, E. 1, s. 1. 1). Hot spring: 1. 

 Area: Eur. 



Meridion Agardh 1847. V. H. Trt. 347. 



*Meridion circulare Ag. V. H. Trt. 347, Tab. XI, fig. 474. 



347 samples (S. 60, S.W. 71, N.W. 15, N. 40, E. 157, s. 1. 4). Hot 

 springs: 12. 



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



