234 Panama Shells. 



4. The Caribbean waters. 



5. West side of America, tropical shores. 



6. southern temperate region. 

 It is also common in a fossil state. 



" Fossile en Italic, en Sicilie, en Moree, a Bordeaux et & Dax, 

 dans les faluns de la Touraine :" Deshayes. 



"Fossile nel Piacentine e nel Sanese ;" Brocchi. 



351. Crepidula siivea. Nov. sp. 



Shell ovate-elliptic : rather thick : within snow white : with- 

 out dingy white, sometimes with a faint tinge of brown : very 

 irregularly concentrically more or less wrinkled, with very dis- 

 tinct striae of growth : apex turned more or less to the right, 

 moderately prominent, marginal : septum longitudinally sub- 

 angular, with a deep sinus at the left and a shallow one at the 

 right : margin thick, exhibiting striae of growth. It closely 

 resembles C. unguiformis, but constantly differs in characters 

 and station. 



Length 1.4 inch ; breadth 1 inch ; height .4 inch. 



Station. Under stones, near low water mark. 



Habitat. Panama ; C. B. A. ! 



45 specimens were collected on the reef. 



352. Crepidtila osculans. Nov. sp. 



Shell elliptical : pale horn color, subtransparent : surface 

 minutely decussated with numerous very small radiating and 

 concentric ridges : apex subterminal, very prominent, not 

 marginal, with the nuclear portion smooth, shining, transparent 

 and slightly directed to the right : septum but little above the 

 margin, extremely narrow or linear, extending around the 

 posterior part of the shell : margin very thin. In some respects, 

 this species is allied to Pileopsis. 



Length .14 inch ; breadth .1 inch ; height .045 inch. 



