no. 1704. A COLLECTION OF SHELLS FROM PERU—DALL. 159 
CYRENA ISOCARDIOIDES Deshayes. 
Plate 26, fig. 4. 
Cyrena isocardioides DEsHAyeEs, Proc. Zool. Soc. of London for 1854, p. 22.— 
Prime, Smiths. Misc. Coll. No. 145, 1865, p. 25. 
Llurona. Tumbes region, from the Estero Bendito. West Colombia, Deshayes. 
These shells were found in some numbers barely covered by the muddy sand and 
rather high above low-water mark. The animal contains such a quantity of salt 
water as to be very unpalatable, even if the flesh*be repeatedly punctured while 
roasting. 
Shell much inflated, rounded trigonal, cordate, thin; anterior end 
evenly rounded; posterior side obliquely declining, subtruncate at 
the extremity; surface smooth except for incremental lines; perio- 
stracum thin, velvety, of an olivaceous brown; beaks large, swollen, 
incurved; shell white with faint violet streaks; hinge plate very narrow, 
teeth small, nearly equidistant from the cardinals; valves white 
inside, with sometimes a little violet near the margins, which are 
entire. Pallial line entire, without the sinus found in other American 
Cyrenas. 
DONAX ASPERA Hanley. 
Plate 28, fig. 7. 
Donax asper HANLEY, Proc. Zool. Soc. of London for 1845, p. 14.—SowrErsy, 
Thes. Conch., vol. 3, 1862, p. 307, pl. 1, fig. 24. 
Almejas. Found at the sand beach of Santa Lucia, mouth of the Tumbes River. 
A small but esteemed comestible, abundant on many beaches. 
Distribution — Central America and southward to Tumbes, Peru. 
Shell triangular, wedge shaped, small, solid, white or purple; 
radiately striate in front; on the short posterior side granulated near 
the angle of the truncation; behind the angle striated; posterior ven- 
tral margin denticulate; posterior area convex below, concave above; 
beaks elevated, the anterior dorsal slope steep. 
The color, as in most donaces, is very variable. On the Lower 
Californian coast shells of this genus, even smaller than D. aspera, 
are washed, thrown, shells and all, into hot water, boiled until the 
juice is extracted and then strained out, leaving a clear broth of 
which the flavor is highly praised. 
IPHIGENIA ALTIOR Sowerby. 
Plate 25, fig. 8. 
Capsa altior SowERBy, Proc. Zool. Soc. of London for 1832, p. 96.—RoEmMER, 
Mon. Dona, 1869, p. 114, pl. 21, figs. 1-4. 
Playeras. From the flats at Capon, 4 to 6 inches deep in the sand, and from a tidal 
lagoon at La Boca Grande, Tumbes. 
Mistribution.—Gulf of California and southward to Tumbes, Peru. 
Shell subtriangular, oblong, arcuate, pale green or rosy under an 
olive periostracum, internally violet; posterior dorsal margin sloping, 
