DALL: MOLLUSCA AND BRACHIOPODA. 325 
U.S. S. “ Albatross,” station 3392, in the Gulf of Panama, in 1270 fathoms, 
hard bottom, temperature 36°.4 F. U.S. N. Mus. 123,032. 
The description is written from an adult with base defective, and a young shell 
of four whorls. The adult aperture may therefore present some features not noted 
here. 
This genus occurs in the Middle Eocene of both the Paris basin and Alabama. 
A recent species, C. migrans Dall, has been described from eighty fathoms in the 
Straits of Florida, and probably further researches into the deep-sea faunas will 
reveal others. So far no specimen with the soft parts or operculum has been 
obtained. 
Seqguenziridae. 
SEGUENZIA Jerrrreys. 
Seguenzia occidentalis Datt, n. sp. 
Shell small, pearly under an opaque dull white outer coat, with five turbinate 
whorls and a small globular, subtranslucent, glossy nucleus; whorls with three prom- 
inent spiral keels, the strongest at the periphery, the others at the shoulder and 
the edge of the base, about equidistant from the suture and each other; the base 
with three smaller more adjacent spirals, and between them and the umbilicus four 
or five still finer spiral threads; axial sculpture in the interspaces of almost 
microscopic elevated arcuate radial lines in harmony with the lines of growth and 
crossed by extremely fine microscopic spiral striae ; base rounded, the umbilicus 
perforate, partly shadowed by the thin reflected edge of the pillar; aperture sub- 
quadrate, deeply widely notched near the suture; the body with a thin wash of 
callus, the pillar vertical, simple, lightly reflected, at the anterior end forming a 
right angle with the anterior margin of the aperture ; operculum wanting. Lon. 
of shell, 2.9; of aperture, 1.7 ; max. diam. 3.1 mm. 
U.S. 8. “ Albatross,” station 3418, off Acapulco, Mexico, in 660 fathoms, sand, 
bottom temperature 39° F. U.S. N. Mus. 123,033. 
The chief features of this species are the perforate umbilicus, the Trochoid 
form, and the three principal carinae, a combination quite sufficiently distinguish- 
ing it from any of the hitherto described Atlantic species. 
Seguenzia stephanica Da tt, n. sp. 
Shell small, whitish, nacreous, shining through a translucent outer coating ; 
with about six whorls and a minute translucent glossy subglobular nucleus ; 
whorls with four strong spiral keels, the posterior pair somewhat nearer the 
suture and each other than they are to the anterior pair, that is, the peripheral 
interspace is widest; the anterior keel of the four forms the margin of the base 
of the last whorl, but the suture is wound on the third keel; base with about 
eight much smaller, adjacent, simple, spiral threads extending to the pillar, the 
