A. E. Verrill — Catalogue, of Marine Mollusca. 
491 
on the anterior part of the body-whorl the cinguli become more uni- 
form in size and more numerous. On the second and third whorls 
the cinguli are large, regular, very prominent, and nearly equal, sep- 
arated by deep concave grooves or sulci, about twice as wide ; on the 
second whorl there are about 9 of these spiral cinguli; on the third 
whorl a few smaller ones begin to appear in the interspaces near the 
suture, and on the fourth whorl most of the grooves, have one or two 
small cinguli; the nine or ten larger primary cinguli can still be dis- 
tinguished on the body-whorl. The whole surface is covered with 
fine, distinct lines of growth which decussate the cinguli and mostly 
cross the ribs somewhat obliquely. The nucleus is rounded and 
remarkably large for the genus (2 mm in diameter), translucent glossy 
brown, nearly smooth for about one turn and a half; the ajtex is 
regular and not obliquely raised. 
The aperture is unusually small and short, elliptical, a little con- 
tracted posteriorly; outer lip thin, well-rounded, the edge receding in 
a broad curve below the suture ; canal short and narrow ; columella 
rather straight, thin, with the folds slightly developed ; the anterior 
end thin, rounded and projecting quite as far as the lip ; the upper 
part of the columella-lip is not excavated, nor distinctly excurved. 
The operculum is small, pale yellow, rounded-elliptical, with the 
nucleus at about the middle of the length and a little to one side of 
the centre. Epidermis thin and smooth. Color of the shell, with 
epidermis, yellowish brown, to dark reddish brown, sometimes with 
small paler spots on the larger spiral ridges; columella whitish, inside 
of aperture pale orange-brown, or light amber. 
Our largest example (female) is 46 mra long; breadth, 21 mra ; length 
of body whorl 29*5 mm ; length of aperture, 2T5 ram ; its breadth (lip 
broken), 12 mm ; length of operculum, 11 •5 mm ; its breadth 9 mm . A 
male has very nearly the same proportions. 
Off Martha’s Vineyard, station 939, in 258 fathoms; station 1032, 
in 208 fathoms, 1881 ; three living examples, male and female. 
This species resembles some of the varieties of B. undatum , but 
besides its more slender and elongated form and more delicate tex- 
ture, it differs decidedly in the character of the spiral sculpture, the 
shortness and small size of the aperture, and in the operculum ; but 
the most striking differences arc in the nucleus and upper whorls, for 
the nucleus is more than twice as large as that of B. undatum (fig. 
10), and different in character, on the second and third whorls the 
spiral cinguli are fewer, and very much more prominent and coarser. 
The character of the nucleus and upper whorls will also distinguish 
Trans. Conn. Acad., Vol. Y. 69 June, 1882. 
