34 ERNST ØSTRUP 



Valva sublineari, apicibus capitatis. Striis marginalibus, area m 

 apicalem latam relinquentibus. 



Hrafnagil (N.) H. Js., in a hot spring, Ulfsbær (N.) B. P. 



Area: Eur. 



This form I consider identical with Hiistedt's var. brevicostata, of 

 which no figure is given. 



Var. linearis Hérib. Hérib. Auv. III, 45, Tab. XIII, fig. 20. 

 15 samples (S. 6, S.W. 5, N. 1, E. 3). 

 Area: Eur. 



Pinnularia intermedia (Lgst.) Cl. Cl. Syn. II, 80. Lgst. Spb., Tab. I, 

 fig. 3 (Nav. int.). 



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

 Area: Eur., Aust., GrL, B. E., Spb., Fz. J. 



Pinnularia lata (Bréb.) Cl. Cl. Syn. II, 81. Grun. Fz. J., Tab. I, fig. 14 



(Nav. lala). 



32 samples (S. 10, S.W. 3, N.W. 4, N. 6, E. 8, s. 1. 1). Hot springs: 4. 

 Area: Eur., As., Am., Aust., Grl., J. M., Fz. J. 



Var. minor Grun. Cl. Syn. 1. c. Grun. 1. c, figs. 16 — 17 (Nav. lat. 

 min.). 



Hofsfjall N.) O. D., Seyôisfjarôarheiôi (E.) H. Js. 



Area: Casp. Sea, J. M., Spb., Fz. J. 



In a sample from Reykjavik (S.W.) H. Js. I have found a Pinn. lata 

 forma minima, of which I give a figure on tab. nostr. Ill fig. 51. Its dimen- 

 sions are: length 27 u. width 8 fi, str. 4,5 in 10 u. 



Tabellarieæ Cl. 1895. Cl. Syn. II, 81. 



Pinnularia Brandeli Cl. var. linearis var. nova, Tab. nost. III, fig. 52. 



Long: 47 u, lat: 8 a, str. 12 in 10 u. 



Valva lineari, apicibus rotundatis. Raphe area hyalina satis 

 angusta, media in parte valvæ in fasciam satis latam dilatata, cincta. 

 Utroque in latere fasciæ striola fere linearis adest. Fissuris termi- 

 nalibus semicircularibus. 



TorfastaMr (S.) A. F., in a hot spring. 



Undoubtedly a somewhat wider striated variant of Pinn. Brand. 



Pinnularia densestriata sp. now, Tab. nost. Ill, fig. 53. 



Long: 50 //, lat: 6,4 ,u, str. 20 in 10 ii. 



Valva lineari, leniter undulata, apicibus rostratis. Raphe area 

 hyalina lata, media in parte valvæ in fasciam latam dilatata, cincta. 

 Striis radiantibus, apices versus convergentibus. 



Hallormstaôr (E.) B. P. 



I am not sure as to the place of this form within the several groups 

 of Pinnularia. Possibly, owing to the close striation, it ought to be 

 classed with Pinn. gracillimæ, against which however speaks the broad 

 area and the transapical fasciæ. 



