3t> 



lib Valves asymmetrical about the transapical plane - MER3DI0N 



Fig. 4o. Meridion circulare , (12), cells 12-80u long, ^-8u vide; 

 3-5 internal costae In lOu; about 15 striae in lOu. 

 X 1000. Widely distributed. 



valve view 



girdle view 



Notes: 



