CLASS PELECYPODA 
45 
Subgenus Barbatia Gray, 1847. 
SECTION FOSSULARCA Cossmann, 1877. 
Area solida Brod. and Sowerby, 1833. 
Proc. Zool. Soc.y 1833. Conch. I conic a, 2; plate 16, fig. 106. 
Shell ovately square, nearly equilateral, thick, solid, very gibbous, 
sides rounded, the posterior obtusely angulated, obsoletely keeled; whitish, 
with scarcely any epidermis; radiately striated, striae elevated, rather indis¬ 
tinctly and irregularly canellated with minute longitudinal striae; umbones 
central; areas of the ligament elongated, somewhat bent inward; liga¬ 
ment diamond-shaped, central. Length, 14; height, 10; diameter, 9.5 mm. 
(Conch. Iconica.) Described as Byssoarca solida. 
Type in Museum Cuming. Type locality, Payta, Peru. 
Range. San Diego, California, to Peru. 
SECTION ACAR Gray, 1847. 
Area reticulata Gmelin, 1792. 
Syst. Nat., 7:3311. Conch. Iconica; Area, plate 16, fig. 108. 
Shell ovately oblong, anterior side rather angulated at the upper part, 
posterior rounded, somewhat concavely compressed, with a keel running 
down from the umbones to the margin; white, with scarcely any epidermis; 
longitudinally fimbriately ribbed, interstices deeply grooved, crossed with 
narrow raised ridges; ribs fimbriately spinous on passing over the keel, 
divaricately rayed across the concave posterior area; area of the ligament 
narrow, lanceolated posteriorly. This is the description of A. divaricata 
Sowerby, which equals the above species. Length, 6.4 mm. (Sowerby.) 
Type in Museum Cuming. Type locality, Island of Annaa (Chain 
Island). 
Range. San Pedro, California, to Ecuador. Also Atlantic. 
Subgenus Scapharca Gray, 1847. 
Area multicostata Sowerby, 1833. 
Proc. Zool. Soc., 1833. Conch. Icomca, 2; plate 4, fig. 23. 
Shell squarely rhomboid, solid, equivalve; sides attenuated and angu¬ 
lated at the upper part, anterior side shorter, ventricosely rounded beneath, 
posterior angularly extended downward; ivory white, covered over with 
a brown horny epidermis, which is a little velvety between the ribs; 
radiately ribbed, ribs about six-and-thirty in number, rather narrow, 
rounded, smooth, anterior ribs slightly granulous; area of the ligament 
rather broad; umbones somewhat approximated. Length, 100; height, 80; 
diameter, 76 mm. (Sowerby.) 
