176 PROCHEDINGS OF THE NATIONAL MUSEUM. VOL. 37. 
TURBO (PRISOGASTER) NIGER Wood. 
Turbo niger Woop, Index Test., suppl., 1828, pl. 6, No. 1—Sowersy, Gen. 
Shells, fascic. 37, 18382, Turbo, fig. 7.—Gray, in Beechey’s Voy., Zool., 1839, 
p. 148, pl. 36, fig. 1. 
From rocks. at west end of Callao water front; from tidal pool on shingle beach at 
La Punta, Callao; dredged in 24 fathoms on the northeast side of San Lorenzo Island; 
and common on the rocks along shore at the Chincha Islands. 
Distribution.—From the Straits of Magellan northward to Pacas- 
mayo, Peru. 
Shell small, turbinate, smooth or spirally striated (especially in 
southern specimens), black, with a white aperture and smooth nearly 
hemispherical white shelly operculum; base imperforate, interior of 
aperture pearly; diameter about 20 mm. 
TEGULA ATRA Lesson. 
Plate 24, fig. 4. 
Trochus ater Lnsson, Voy. Coq., 1830, p. 344, pl. 16, fig. 2. 
With the last species. 
Distribution.—From the Straits of Magellan northward to Pacas- 
mayo, Peru. 
Shell imperforate, conical, more or less depressed; heavy, solid, 
lusterless black; with about six moderately convex, nearly smooth 
whorls; suture impressed; last whorl obtusely rounded at the periph- 
ery, base flattish, concave in the center, eroded and light purple in 
front of the aperture; outer lip with a black margin, pearly within; 
a white callus, bearing a spiral rib and somewhat excavated, in the 
umbilical region; an obscure tubercle at the end of the pillar. Oper- 
culum horny, multispiral; diameter of shell about 40 mm. 
This is the largest of the black trochoid species for which the coast 
is noted. 
TEGULA PATAGONICA Orbigny. 
Trochus patagonicus OrBIcNy, Voy. Am. Meér., vol. 5, 1840, p. 408, pl. 55, figs. 
1-4.—Puuupert, Conch. Cabinet, 2d ed., Trochus, p. 225, pl. 34, fig. 12. 
Taken on the shore rocks at Lobos de Afuera Island. 
Distribution.—San Blas, Patagonia, northward to the Lobos 
Islands, Peru. 
Shell orbiculate conic, thick, umbilicate, axially granulose-sulcate, 
uniform brownish or purplish, spire obtuse; whorls five, subcarinate; 
sutures excavated, aperture rounded, columella bidentate; diameter | 
about 14 mm. 
TEGULA TRIDENTATA Potiez and Michaud. 
Trochus tridentatus Pottmz and MicHaup, Gal. de Douai, vol. 1, 1838, p. 321, 
pl. 29, figs. 16-17.—Kiener, Icon., Trochus, pl. 57, fig. 2. 
Dredged in Sechura Bay, in 5 fathoms, also taken on the rocks in various places 
about the harbor of Callao. 
Distribution.—F rom Talecahuano, Chile, northward to Sechura 
Bay, Peru. 
