ARCA. Panama Shells. 263 



rately excurved ; anterior margin well rounded : dingy white, 

 with blackish brown epidermis: with numerous very pro- 

 minent but very narrow linear ribs, which are often alter- 

 nately large and small, and of which a few at each extremity 

 are a little stouter and are subnodulous ; with a few indistinct 

 concentric lines : umbones prominent, flattened : area of the 

 ligament very narrow, anteriorly widened abruptly: margins 

 of the interior finely and irregularly crenulated : middle teeth 

 very small. The epidermis is between pilose and lamellar, 

 with the points long posteriorly. 



Length 1.3 inch ; height .85 inch ; breadth .65 inch. 



Station. Under stones near low water mark. 



Habitat. Taboga and Panama ; C. B. A. ! 



60 specimens were collected, mostly at Taboga, 



425. Area tuberculosa. 



Synonymy. 



Area tuberculosa Sowb. in Proc. Zool. Soc. Lond. p. 19. Feb. 1833. 



- Mull. Syn. Test. Viv. p. 179. 1836. 



Phil. Abbild. I. pi. 1. f. 2. Mar. 1843. 



Reeve Conch. Icon. pi. 3. f. 18. Jan. 1844. 



Hanley Descr. Catal. p. 161. 1845? 



Station. Found at low water at the roots of the mangrove 

 trees ; Cuming ! Sowerby : also Reeve. Our specimens were 

 found in impalpable mud, under a mangrove thicket, near high 

 water mark. 



Habitat. Real Llejos ; Cuming ! Sowerby : also Reeve. 

 Pacific Ocean, Central America ; Philippi. 

 South America; Hanley. 

 Real Llejos ; Jay. 



Mazatlan ; Lt. Green ! Mus. Essex Inst. 

 Panama ; C. B. A. 1 



