236 Panama Shells. FISSUKELLIDJ3. 



355. Fissurella alta. Nov. sp. 



Shell subconic, high : dingy white, often more or less covered 

 with broad ashy black rays, which may be seen through the 

 shell : with prominent radiating ribs, of which the alternate 

 ones are excessively developed, and intermediate small raised 

 lines ; with many concentric ridges, which are less prominent 

 than the larger radiating ribs, and more so than the others: 

 summit nearer to and somewhat inclined towards the anterior 

 extremity : fissure small, ovate-elliptic : margin pectinated by 

 the radiating ribs. 



The following are the dimensions of a very large and high 

 shell and of another of average size : 



Height .42 inch ; length .55 inch ; breadth .41 inch. 

 a _22 " " .42 " " .29 " 



Station. Unknown. 



Habitat. Panama ; C. B. A. ! 

 26 specimens were obtained. 



356. Fissurella macrotrema. 



Synonymy. 



Fissurella macrotrema Sowb. in Proc. Zool. Soc.Lond. p. 125. Nov. 1834. 



Mull. Synop. Nov. Test. Viv. p. 155. May 1836. 



Sowb. Conch. 111. No. 33. pi. 74. f. 41. 1841. 



Chenu. 111. Conch, pi. 1. f. 14. 1843. 



Reeve Conch. Icon. pi. 5. f. 31. Aug. 1849. 



Station. Under stones on the shore ; Cuming ! Sowerby. 



Habitat. Gallapago Is. and Eeal Llejos ; var's at Lobos I. 

 and Lambeyeque, Peru ; Cuming ! Sowerby : also 

 Miiller. 



Gallapago Is. ; Cuming ! Keeve. 

 Taboga; C. B. A. ! 



We collected 5 specimens, which are somewhat narrower 

 than the figures in Sowerby and in Keeve. 



