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 Hupe 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 2G, fig. 2. 



Ostrea columbiensis PIanley, Proc. Zool. Soc. of London, for 1845, p. 107. — Sow- 

 ERBY, in the Conchologia Iconica, Ostrea, 1871, pi. 7, fig. lOa-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 C^alifornia 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 roimded 

 trigonal, externally more or less lamellose and somewdiat 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 0. 

 cMlensis. 



PECTEN PURPURATUS Lamarck. 



Plate 2G, figs. 5, 6. 



Pecten purpuratus Lamarck, Anim. s. Vert., vol. 6, pt. 1, 1819, p. 166. — Sowerby, 

 Thesaurus Conch., vol. 1, 1843, p. 53, pi. 15, fig. 113; pi. 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. 



Distribution. — From Coquimbo, Chile, northw^ard to Ecuador. 



Shell orbicular, moderately convex, subequivalve, rather thin, with 

 about 26 flat-topped ribs, laterally fringed, and separated by chan- 

 neled interspaces; colors w^hite, 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. 



