17 



j^uidied from it by being flrongly flriated in a radiated 

 manner, the inferior valve from the lower anterior angle, 

 and the fuperior one from the upper pofterior margin; 

 thefe are croffed by very fine flrice, which give a taint 

 reticulated appearance: the angles of the valves are much 

 more fliarp and pointed, and particularly the apex : the 

 dorlal valve is compreffed at the fides, and brought to 

 a fine carinated edge, whereas in the other it is rounded, 

 and only fub-carinated down the middle: This is a re- 

 markable chara61er, and fufficient to difcriminate the (hell 

 if all others were wanting : the fuperior valves are alfo 

 irtach more compreffed, which makes the fhell extremely 

 thin or flat on the pollerior fide. Length one inch : 

 breadth not quite three quarters : colour bluifli-w^hite. 



This fpecies is rarely found with the former; we have 

 taken it from a piece of drifted wood on the fouth coafl 

 of Devovpiire, from half an inch in length to the fizc 

 before mentioned ; the conneding cartilages and pedicle 

 bright orange-red. 



o. 



L. with a compreffed fub-triangular fhell of five valves. Sulcata. 

 the inferior ones wrought with fiiieen flrong ribs diverg-TAs. 1. f. 6. 

 ing from the lower anterior angle; that which runs along 

 the front is larger than the relt, and firms a margin; the 

 two fuperior valves form a pointed apex, and narrow 

 downwards to a point, furniflied with feven or eight ribs 



D with 



