246 Panama Shells. OSTR^EIDJS. 



the incremental stride : nacre extremely brilliant, with delicate 

 changeable colors. 



Attached to ledges of rock by the greater part of the lower 

 valve. It occurs near half tide level. 



It is not common : we collected only 3 specimens on the reef 

 at Panama. 



382. Ostrea . Sp. indet. c. 



Synonymy. 



? 0. Columbiensis Hanley, P. Z. S. Lond. p. 107. Oct. 1845. 



Bather small, more or less pentangular, and short but not 

 plicated. 



Attached to stones, rocks, and other shells, near half tide 

 level : the lower valve is attached by rather more than half of 

 its surface, and then abruptly rises from the attached part so as 

 to form a deep cavity. 



0. Columbiensis Hani, was found by Mr. Cuming attached to 

 rocks at half tide at St. Elena. At Panama our shell is not 

 rare, although we took only 15 specimens. 



383. Ostrea - . Sp. indct. d. 



Like 0. l>orealis. 



Usually occurs in clusters. 



It was brought from some place near Panama which we did 

 not visit. We obtained 35 specimens. The flavor is superior 

 to that of 0. virginica or 0. lorealis. They were sold in Pa- 

 nama at a dime each. 



384. Otrea - -. Sp. indet. e. 



A small plicated species. The animal has a bitter flavor. 

 Attached to rocks and stones from three quarters to one quar- 

 ter tide level. A small var. grows on Nerita scabn'costa. 



This species covers many parts of the reef at Panama in great 

 profusion. We collected 330 specimens. 



