DALL: MOLLUSCA AND BRACHIOPODA. 309 
a single sharp suleus at the extreme margin, running between two slightly ele- 
vated lamellac. Alt. of type specimen, 22; of aperture, 17 ; max. diam. 16.5 mm. 
À larger specimen is 23.5 by 20 mm. 
U. S. S. “ Albatross,” stations 2799, 2800, 9801, 2803, 2804, in the Bay of 
Panama, in 7 to 47 fathoms, mud; also, dead specimens, at stations 3354 and 
3392, in 399 to 1970 fathoms, muddy bottom. U. 8. N. Mus. (types) 46,446. 
The young shell has darker, faint brownish streaks obscurely disposed in two or 
three Spiral bands. The adult is without perceptible pattern. The shell belongs 
to the group of “maroccana,” under which so many distinct forms have been 
lumped by undiseriminating authors, and is perhaps nearest to some varieties of 
the West Indian N. Zivida Philippi, which has a differently sculptured operculum. 
Natica (Cochlis) scethra Dar, n. sp. 
Plate 11, figure 5. 
Shell small, moderately elevated, with about three whorls, exclusive of a smooth, 
Polished nucleus of two and a half whorls, which changes abruptly into the adult 
Sculpture; suture distinct; color pale brown with three obscure pale bands, one 
about the region of the shoulder, another a little in front of the periphery, and 
the third, less distinct, on the base; all rather ill defined; whorls smooth, except 
between the shoulder and the suture, where start numerous (on the last whorl 
twenty-six), sharp, very obliquely retractive, narrow wrinkles; aperture ovate, 
Outer lip areuate, thin, simple, sharp; body with a well-marked callus, terminat- 
Ing at a notch at the posterier end of the umbilicus; ab the pillar is a pad, formed 
by the end of a Nattish ridge, which winds into the depths of the umbilicus, 
leaving a narrow chink to the left of the pad; anterior lip slightly thickened ; 
operculum flat, white, with brownish clouding, a small patch of roughened callus 
obscuring the spiral part externally; outer edge elevated, with two deep, very 
Narrow sulci revolving within it, the interspace forming à single flat-topped rib. 
Height of shell, 17.05 of last whorl, 15.5; of aperture, 11.5; max. diam. 16.0 mm. 
U. S. S. * Albatross,” station 3391, Gulf of Panama, in 153 fathoms, mud, 
bottom temperature 559,8 F. U. S. N. Mus. 123,048. 
POLINICES MONTFORT. 
Uler (Anonymous) Mus. Calonn., 1797, p. 21. 
Albula Bolten, Mus. Bolt., 1798, p. 20; not Albula Gronovius, 1768. 
Polinices Montfort, Conch. Syst., 1810, 2, p. 223; type, Nerita mamilla Linné. 
> Neverita Risso, Hist. Nat. Eur, Mér., 1826, 4, p. 147; type, N. josephinae Risso. 
> Euspira Agassiz, in Sowerby, Min. Conch., 1842, German ed., p. 14. First spe- 
cies, N. glaucinoides Sowerby, = N. labellata Lamarck, 1804. 
> Lunatia Gray, P. Z..8. Lond, 1847, p: 149; type, N. ampullaria Lamarck 
(= Euspira Ag.). 
