No. 1704. A COLLECTION OF SHELLS FROM PERU—DALL. 149 
the muscular scars white; the lower valve deep, rugose-scaly, the 
upper valve nearly flat. 
This species is reported by Hupé to have as good a flavor as the 
edible oyster of Europe, yet the natives of South America will eat it 
only when cooked. It seems from an economic standpoint to be the 
most important species of the genus in the region where it occurs. 
It is easily distinguished from the following species in any of its 
mutations by the white or pale green margin of the valves. 
OSTREA COLUMBIENSIS Hanley. 
Plate 26, fig. 2. 
~ Ostrea columbiensis HANLEY, Proc. Zool. Soc. of London, for 1845, p. 107.>Sow- 
ERBY, in the Conchologia Iconica, Ostrea, 1871, pl. 7, fig. 10a-b. 
From the roots of the mangroves near the mouth of the Rio Tumbes; on the beach 
near the Estero Bendito; and bought in Callao, where they had been brought from 
the Tumbes region. Ostra of the fishermen. 
Distribution—From the Gulf of California south to Coquimbo, 
Chile. 
Shell smaller than that of the preceding species, streaked with 
purple externally, the margins of the valves and the muscular scars 
purple or tinged with purple; ligamentary area broad, the beak of 
the lower valve strongly laterally recurved; form irregularly rounded 
trigonal, externally more or less lamellose and somewhat obscurely 
radiately ridged. 
This species, distinguished by its purple scars and margins, is 
gathered for sale in the markets, but never attains the size of O. 
chilensis. 
PECTEN PURPURATUS Lamarck. 
Plate 26, figs. 5, 6. 
Pecten purpuratus LAMARCK, Anim. s. Vert., vol. 6, pt. 1, 1819, p. 166.—SoweErBy, 
Thesaurus Conch., vol. 1, 1843, p. 53, pl. 15, fig. 113; pl. 16, figs. 123-125. 
Concha abanico or conchitas. Taken near San Lorenzo Island, in Callao Bay, in 
about 15 feet of water, and in Sechura Bay, half-way between Bayovar and Mata- 
caballa. 
Mstribution.—From Coquimbo, Chile, northward to Ecuador. 
Shell orbicular, moderately convex, subequivalve, rather thin, with 
about 26 flat-topped ribs, laterally fringed, and separated by chan- 
neled interspaces; colors white, rose color, and different shades of 
purple distributed in an irregular manner; the interior zoned with 
blackish purple. 
The large adductor muscle of this species is a delicious morsel 
‘when delicately cooked. The Chilean name for the species is Ostion. 
