174 PROCEEDINGS OF THE XATIOXAL MUSEIUI. vol.37. 



CREPIDULA DILATATA Lamarck. 



Crepidula dilatata Lamarck, Anirn. s. Vert., vol. 6, 1822, pt. 2, p. 25. — Broderip, 



Trans. Zool. Soc. London, voL 1, 1834, p. 203, pi. 28, fig. 11. 



On oysters and other objects in about 5 fathoms, near Matacaballa, Sechura Bay; 



also on the beaches. Also from rocks at the north end of Callao water front, and on 



the north shore of San Lorenzo Island; called by the fishermen " piques." Found 



breeding in February. 



Distribution. — From the Straits of Magellan northward to Mazatlan, 

 Mexico, and at the Galapagos Islands. 



Shell slipper shaped, rounded, brownish with a white septum inter- 

 nally; upper surface convex, varying from nearly smooth to lamellose, 

 the general form irregular, conforming to the individual situs. 

 Length about 30 nim. 



CREPIDULA CREPIDULA Linnaeus. 



Patella crepidula Linn.eus, Mus. Lud. Ulricte, 1764, j). 689. — Favanne, Conch., 



pi. 4, fig. D. 

 Crepidula ungui/ormis Lamarck, Anim. s. Vert., vol. 6, 1822, pt. 2, p. 25. — 

 GuALTERi, Test., pi. 69, fig. H. 

 In dead shells on the flats at Capon. 



Distribution. — The whole Peruvian province, in dead shells, and 

 northward to the Gulf of California. 



Shell oval, flattened or tlorsally concave, white, corresponding to 

 the curve of the shell in which it is found; of irregular outline, con- 

 forming to its situs; length about 35 mm. It has no economic value. 



CREPIDULA ONYX Sowerby. 



Plate 23, figs. 2, 5. 



Crepidula onyx Sowerby, Gen. Shells, fascic. 23, 1824, Crepidula, fig. 2. 

 In various parts of Sechura Bay, adhering to oyster shells and other objects; and 

 dredged off Matacaballa in about 5 fathoms. 



Distribution. — From San Pedro, California, southward to Chile. 



Shell slipper shaped, oval, with a smooth convex ujjper surface, a 

 short, hardly prominent apex, and the internal septum white, with a 

 nearly straight margin, and covering nearly half of the cavity of the 

 shell; the exterior is more or less painted with brown spots, streaks 

 or markings on a lighter ground; the interior usually dark brown, the 

 septum white. It reaches a length of 45 mm. 



The flesh of the analogous C. fornicata Lamarck, of the Atlantic 

 coast of North America is regarded as a dainty in the raw state by 

 epicures, but there is no information as to the economic use of the 

 present species. The other species of the genus found in Peru are too 

 small to be of much importance. 



