MERIDION. 



Tribe XIII. Meridione/E. 



347 



Frustules and valves cuneate, united in a spiral filament 



Meridion. 



GENUS 63. MERIDION AGARDH., 1824. 



Differs from the genus Diatoma by the cuneate form of the valves 

 and of the frustule in girdle view. Endochrome as in the following 

 genus. 



Fig. 101. Meridion circulare. 



This genus ought to be suppressed, but in that case it would be logically 

 necessary to suppress all cuneate genera, such as Gomphonema, etc. 



Wl. circulare Ag. (Ktitz., Baa, pi. 7, f. 16 ; h.v.h. Ati, pi. 51, 



f. 10-12* ; Type No. 343), plate 11, fig. 474. 



Valves oval, lanceolate, or clavate, with apices rounded, obtuse, showing 

 transverse costa? rather distant (about 3 in 1 c.d.m.) ; pseudo-raphe indistinct. 

 Stria? fine, about 16 in 1 c.d.m. Girdle face cuneate, with margins appearing 

 somewhat undulated by the beginnings of the costre, which terminate 

 insensibly near the connecting zone. Frustules united in a spiral filament. 

 Length, 2 "5 c.d.m. 



Fresh water. Not very rare. England (Norman), Scotland, Ireland (O'Meara). 



