OSTEEA. Panama Sheik. 245 



318. Anomia tenuis. Nov. sp. 



Shell orbicular : flat, extremely thin : white, subtransparent, 

 pearly: externally somewbat uneven: upper scar large, 

 rounded, with the lower side arcuated : two lower scars small, 

 circular, equal: anterior one nearly entering the arcuation of 

 the upper scar ; posterior one near the other, with the upper 

 margin as high as the centre of the other. 



Diameter about .85 inch. 



Station, — Near low water mark. 



Eahitat. — Panama ; C. B. A. I 

 3 specimens were obtained. 



379. Anomia . Sp. indet. a. 



A very small yellow shell with the convex valve excessively 

 convex, and the margin lobate. Although only 1 valve was 

 found, it is obvious that it belongs to a very distinct species. 



380. Ostrea . Sp. indet. a. 



Rather large and ovate ; with the upper valve radiately cor- 

 rugated, with many notches on both sides of the hinge : lower 

 valve attached to a ledge of rock by the whole of its surface : 

 on this account it is rarely possible to detacb. a specimen entire. 

 It occurs more commonly near half tide level. It is rather com- 

 mon, but not abundant on the reef at Panama. We collected 

 only 6 specimens. It is an edible species of excellent flavor. 

 During the recess of the tide the natives open the shells on the 

 rocks, without detaching the lower valves, and collect the soft 

 parts in a calabash. 



381. Ostrea . Sp. indet. b. 



Rather large and solid, with both valves strongly notched on 

 both sides of the hinge : surface without sculpture other than 



JULY, 1852. 62 Aim. Lire. Nix. Hut. 



