262 Panama Sheik. arcid^:. 



rounded: dorsal margin somewhat oblique: white: with au 

 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 l.X inch. 



Station. — Unknown. 



Habitat. — Panama ; 0. B. A. { 

 10 specimens were obtained. 



423. Area soIida« 



Synonymy. 



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



Miill. Syn. Test. Viv. p. 186. 1836. 



Area Reeve Conch, Icon. pi. 16. f. 106. May 1844. 



Hanley Descr. Catal. p. 153. 1845 ? 



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



Station. — Under stones ; Cuming I Sowerby : also Eeeve. 

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



Ealitat.—Pajta.; Cuming! Sowerby; also Eeeve: also Or- 

 bigny. 



Peru ; Hanley. 



Payta ; Jay : Lt. Green I Gould MSS. 



Panama and Taboga : C. B. A. 1 

 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- 



