= 
514 A. E. Verrill— Catalogue of Marine Mollusca. 
with a long, tapering, acute spire. Whorls eight, broadly and evenly 
rounded ; suture somewhat impressed, but not deep, frequently nar- 
rowly channelled. Surface, except anteriorly and on the canal, desti- 
tute of spiral lines, and of any indication of ribs, but covered with 
very close, almost microscopic lines of growth, which give the surface 
a dull appearance, when dry ; on the canal and extending to the an- 
terior part of the body-whorl are a number of distinct spiral lines, 
becoming faint opposite the middle of the aperture ; fine, microscopic, 
spiral striations sometimes appear on the lower whorls. The nucleus 
is larger than in A. rosacea, rounded, depressed, and spiral, but 
somewhat mammillary. The aperture is small, oblong-ovate; the 
outer lip is sharp at the edge, but in adult shells has a distinct thick- 
ening a little back from the margin; the inner surface is usually 
smooth, but in some adult specimens there are four or five small, 
transversely oblong tubercles, back from the margin, and a larger, 
conical tubercle at the base of the canal. Columella sigmoid, a 
little excavated in the middle, and with a distinct, raised, spiral fold 
at its inner edge, anteriorly ; canal short, open, very slightly curved. 
Epidermis thin, closely adherent, minutely lamellose along the lines 
of growth, pale greenish gray, or yellowish white. 
Length of one of the largest specimens, 12"; breadth, 4™"; length 
of body-whorl and canal, 7"; length of aperture, 5"; its breadth, 
1°8"™™. Stouter and shorter examples occur, 
Off Martha’s Vineyard, in 65 to 487 fathoms, 1880 and 1881,—U. 
8. Fish Com. Off Chesapeake Bay, 300 fathoms,—Capt. Tanner, 
Taken at many stations. At 870 and 876, it occurred in considerable 
numbers. 
This species resembles A. rosacea, of which I formerly supposed it 
to be a deep-water variety. A more careful examination of a larger 
and better series convinces me that they are distinct. The present 
species is a more slender and elongated, and far more delicate shell, 
and is destitute of the impressed spiral lines that cover the whorls, 
both in that species and A. //olbéliii,* and is without any traces of 
transverse ribs, on the upper whorls. The fold on the columella-edge 

*T regard A. Holboilii (Méller) of Greenland, as different from the true A. rosacea 
Gould, of New England. The latter is a stouter shell, with broader aperture, and is 
not distinctly transversely ribbed, like the former, except on the whorls next to the 
nucleus. Moreover. the nuclear whorls differ. I have compared Greenland specimens 
directly with our own. If not a distinct species, it is certainly a very marked variety. 
The true A. rosacea occurs from off Chatham, Cape Cod, 16 fath.! to the Gulf of St, 
Lawrence! Mass. Bay, 15 to 25 fathoms! 
