262 Panama Shells. ARCIDJE. 



rounded: dorsal margin somewhat oblique: white: with an 

 epidermis, which is greenish brown on the young shell, and 

 brownish black on an old shell : with forty to forty-four ribs, 

 which are larger and more sharply angled posteriorly : umbones 

 prominent, flattened, not angulated : area of the ligament nar- 

 row, depressed : margins of the interior pectinated by the ribs : 

 teeth small. It resembles A. tuberculosa Sowb. 



Length 2.2 inches ; height 1.3 inch ; breadth 1.1 inch. 



Station. Unknown. 



Habitat. Panama ; C. B. A. ! 

 10 specimens were obtained. 



423. Area solida. 



Synonymy. 



Byssoarca solida Sowb. in Proc. Zool. Soc. Lond. p. 18. Feb. 1833. 



. Mull. Syn. Test. Viv. p. 186. 1836. 



slrca . Reeve Conch. Icon. pi. 16. f. 106. May 1844. 



Hanley Descr. Catal. p. 155. 1845 ? 



. Orb. Voy. Amer. Merid. Moll. p. 633. 1846. 



Station. Under stones ; Cuming ! Sowerby : also Reeve. 

 Our specimens were found under stones, near low water mark. 



Habitat. Payta ; Cuming! Sowerby; also Reeve: also Or- 

 bigny. 



Peru; Hanley. 



Payta ; Jay : Lt. Green ! Gould MSS. 



Panama and Taboga : C. B. A. ! 

 60 specimens were collected. 



424. Area (Byssoarca) Tabogensis. Nov. sp. 



Shell not much elongated, not very inequilateral; inferior 

 margin nearly straight, a little gaping for the passage of 

 the byssus ; posterior margin oblique, rectilinear or mode- 



