NO. 1264. ILL USTRA TIONS OF AMERICAN SHELLS— BALL. 515 
Range, from the above locality northward to Bering Sea, being 
obtained off the Oregon coast in 277 fathoms, and at Unalaska in 68 
to <S5 fathoms. 
This elegant species belongs to the same group as the preceding, and 
is notable for its numerous rounded whorls and deeply constricted 
suture, and when fresh for its peculiar pale green color, which fades 
in a few years, in the cabinet, to a greenish gray. 
PLEUROTOMA (ANTIPLANES) SANTAROSANA, new species. 
Shell elongated, slender, acute, with twelve whorls, of an olivaceous 
or pinkish brown; the interior of the aperture of a pale rufescent hue; 
whorls rounded, suture very distinct, sculpture chiefly of incremental 
lines and a faint spiral striation mostly below the peripher}-; anal 
fasciole limited by slightly raised lines; nucleus small, inflated, smooth; 
aperture narrow, with a short wide canal; pillar solid, short, obliquel}^ 
truncate; outer lip thin, produced, with a deep anal sulcus a little in 
advance of the sutural margin of the whorl. Operculum normal. Lon. 
of shell 36, of aperture and canal 11,5; max. diam. 9 mm. 
Dredged off Santa Rosa Island, California, in 53 fathoms, sand, at 
station 2902, by the U. S. Fish Commission steamer Albatross in 1889; 
bottom temperature 45^ F. U.S.N.M., 109198. 
This elegant species is the most slender and elongated of the group, 
so far as 3^et known, and is easily distinguished by that character and 
by the number of its whorls from any of the others. 
PLEUROTOMA CIRCINATA Dall. 
Plate XXXVI, fig. 1. 
Meurotoma circinata Dall, Proc. Cal. Acad. Sci., V, April 1873, p. 62, pi. ii, 
fig. 5 — AuRiviLLius, Vega exp. vet. arb., IV, 1885, p. 353, pi. xiii, figs. 1,2. 
Mangilia {Aforia) circinata Dall,, Rep. Blake Gastr. , Bull. Mus. Comp. Zool., 
XVIII, Feb. 1889, p. 99. 
Fleurotoma insigiiis Jeffreys, Ann. Mag. Nat. Hist, for Aug., 1883, p. 120. 
Captains Bay, Unalaska, in 60 fathoms, Dall; northwestern part of 
Bering Sea in 55 fathoms, Vega expedition. U.S.N.M., 108995. 
This fine species was first figured from a more or less defective 
specimen, but has since been obtained in considerable numbers, living. 
It is not known from north of Bering Strait, though Jeffre3^s referred 
it to the Icy Sea of Siberia. The Vega specimens were dredged south- 
west of St. Lawrence Island, Bering Sea, in latitude 62"^ 39' and west 
longitude 177^ 05'. Jeffreys was mistaken in supposing it to be 
inoperculate. 
PLEUROTOMA CALLICESTA, new species. 
Shell small, subelongate, with the aperture shorter than the spire, 
and six or more whorls; white, covered with a pale olive green 
