No. 1704. A COLLECTION OF SHELLS FROM PERU—DALL. L75 
TROCHITA TROCHIFORMIS Gmelin. 
Plate 28, fig. 1. 
Patella trochiformis GMELIN, Syst. Nat., vol. 8, 1791, p. 3693. 
Calyptrea dilatata SowERBY, Gen. Shells, fascic. 23, 1824, fig. 9. 
Picachos. From the beach at Pisco. 
Distribution. From Panama southward to Chile. 
Shell conical, flattened on the slopes, with a spiral suture giving 
the effect of a spire; the surface radiately ribbed with rounded riblets, 
the color yellowish; below rounded with a more or less spiral septum 
of a white color; the dome of the shell brownish or whitish, the margin 
suborbicular when not disturbed by its situs. The elevation of the 
shell is very variable, and the diameter will average about, 30 mm. 
This is a very characteristic species of the Peruvian province, but 
of no particular economic significance. 
SINUM CONCAVUM Lamarck. 
Sigaretus concavus LAMARCK, Anim. s. Vert., vol. 6, 1822, pt. 2, p. 208.—SowERBy, 
Gen. Shells, fascic. 19, 1823, Sigaretus, fig. 1. 
From muddy sand on the inside beach at Capon (one young specimen). Caracol 
tapadera of the fishermen. 
Distribution.—Between the equator and lat. 25° 30’ S., and at the 
Galapagos Islands. 
Shell flattened, paucispiral, the last whorl much the largest; spi- 
rally closely sulcate, with a wide aperture and gyrate pillar; color 
livid flesh color to pale brownish. 
The shell in the adult is nearly covered by the fleshy parts. The 
animal plows its way under the sand, drills holes in the shells it 
encounters and sucks the juices of its prey. It 1s economically inju- 
rious through its destruction, especially in their younger stages, of 
edible bivalves. 
TURBO MAGNIFICUS Jonas. 
Turbo magnificus Jonas, Zeitschr. fiir Malak., vol. 1, 1844, p. 167.—Puuvippr, 
Abb. u. Beschr. neue Conch., vol. 2, 1847, p. 25, pl. 6, fig. 1. 
Dead shells and an operculum on the beach at Lobos de Afuera Island. 
Distribution.—From Manta, Ecuador, south to Callao, Peru, and 
the Lobos Islands. 
Shell turbinate, ovate conic, turgid, imperforate, spotted or mar- 
bled with violet and white on an olivaceous or dark-greenish ground; 
whorls rounded, delicately axially striated; obscurely angulated 
above, on the spire; suture distinct, not channeled; aperture large, 
circular, internally pearly with an opaque margin; columella simple, 
callous above; operculum nearly smooth externally. A rare shell, 
probably without economic importance. 
