SYNEDRA. 



3*5 



II. ARDISSONIA. Valve furnished with two or more sulci. 



** Valves furnished with two marginal sulci. 



i'O s 



1 



I 



= I t 



V. 







?! 



I 



II- 



?! -- 



I 



fe 



3'S 











S. crystallina (Lyng.) Kutz. 



(Bac, p. 69, pi. 16, f. 1 ; H.V.H. Atl., pi. 42, 

 f. 10* ; Type No. 305), plate 10, fig, 435. 



Valve very long, linear, inflated at the apices 

 and median portion with broad, very distinct 

 sulci, distant from the edges of the valve ; striae 

 fine, 12 in 1 c.d.m., formed of strong puncta, 

 absent at the apices of the valve, which are 

 covered with granules arranged in radiant lines. 

 Length, about 50 c.d.m. 



Marine. Not yet found in Belgium. England. Ireland 

 (O'Meara). 



a. b. 



Fig, 72. Ardissonia fulgens. 



a. Valve view, 



b. Girdle view. 



