168 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 37. 
surface with revolving striz; spire acute, shorter than the body 
whorl; color white, gray, or olivaceous, with chocolate clouding 
especially on the back of the body whorl, which is sometimes nearly 
all chocolate colored; length 18 mm. 
These small shells have no economic value in themselves; but they 
drill the very young oysters when about 10 mm. in diameter, pierce 
the thin shell, and suck the juices of the animal. If very numerous 
they might be a serious detriment to the maintenance of growing 
oysters. 
ASTYRIS UNICOLOR Sowerby. 
Columbella unicolor SowERBy, Proc. Zool. Soc. of London for 1832, p. 119.— 
Reeve, Conch. Icon., Columbella, pl. 19, fig. 105. 
Dredged in Callao harbor, in 24 fathoms, near San Lorenzo Island. 
Distribution.—From Chiloé Island northward through Chile, Peru, 
and the Galapagos Islands. 
Shell very small, ovate, smooth with revolving striz near the 
canal; color chocolate or chestnut brown, with or without a lighter 
band revolving on the periphery; aperture brownish within; outer lip 
and pillar with a few obscure denticles in the adult; length about 
12 mm. 
This small shell, remarkable for its wide geographic range, has no 
economic relations. 
ALECTRION (HIMA) DENTIFERUS Powys. 
Nassa dentifera Powys, Proc. Zool. Soc. of London for 1835, p. 95.—ORBIGNyY, 
Voy. Am. Mér., vol. 5, 1841, p. 432, p!. 61, figs. 22-23. 
Dredged in about 9 fathoms, muddy bottom, in Ancon Bay. 
Mstribution.—Coasts of Chile and Peru, from Valparaiso north- 
ward to Panama. 
Shell small, turrited, rather thin, obscurely reticulately sculptured, 
chocolate brown, inside and out, with occasionally a paler peripheral 
spiral band; outer lip sharp, thin, in the adult having an obscure 
varix behind it; the sculpture variable in strength; length 20 mm. 
This small and unattractive species has no economic importance. 
CONCHOLEPAS CONCHOLEPAS Bruguiére. 
Plate 22, fig. 1. 
Buccinum concholepas BruGururReE, Encycl. Méth., 1789, p. 252.—Dittwyn, Rec. 
She vols 18i7sps6lle 
Concholepas peruvianus LAMARCK, An. s. Vert., vol. 7, 1822, p. 252.—Tryon, Man. 
Conch., vol. 2, 1880, p. 199, pl. 162, figs. 314-316. 
Pata de burro, of the southern region. Common on some of the rocks some yards 
from shore and at or below low-water line. 
Distribution.—Chincha Islands. Mollendo, and south to the Magel- 
lanic region, Also northward, according to E. von Martens, to the 
west coast of Mexico. 
