- 

A, E. Verrill— Catalogue of Marine Mollusca. 517 
Although a much thinner and far more delicate shell, this species 
has considerable resemblance to ZL. heros, externally, but the whorls 
are more swollen and the suture more impressed, while the lines of 
growth are more flexuous. The best distinctions are to be found in 
the nature of the columella margin and consequent form of the aper- 
ture, and in the umbilicus. In this species the upper part of the 
aperture is encroached upon by the swollen body-whorl, and then the 
columella margin rapidly recedes with a deep sinuous concave bend, 
above the umbilicus, causing a sudden widening of the shell-aperture 
at the middle; this incurvature of the columella is very conspicuous 
in a profile view, looking into the aperture, and renders the interior of 
the shell visible far within. In Z. Aeros no such abrupt curvature of 
the columella occurs, its outline forming only a slightly flexuous curve. 
In Z. levicula there is no thickened callous behind the umbilicus, 
the margin of the lip being then reflexed and thin. The umbilicus is 
well-marked and deep but not so large as usual, even in the shallow- 
water variety of Z. heros.* Our best specimens of ZL. levicula have a 
rich, chestnut-brown interior. 
In the localities where we have dredged this species we have also 
taken large egg-capsules, probably belonging to it, coated with sand 
and shaped like those of Z. heros, but with the cells very much larger, 
and so prominent or swollen as to rise above the surface. Egg-cap- 
sules of the same kind were dredged on Stellwagen’s Bank, in 14 to 
42 fathoms, 1879, but we did not take this shell at those localities. 
Amaura candida Miller. 
Kréyer’s Tidsskr., iv, p. 80, 1842. 
H. and A. Adams, Genera, i, p. 214, pl. 22, fig. 9. 
This Greenlandic species has been recorded from the Gulf of St. 
Lawrence, by Whiteaves. 
Marsenina glabra Verrill. 
Oxinoé glabra Couthouy, Boston Journ. Nat. Hist., ii, p. 90, pl. 3, fig. 16, 1838. 
Lamellaria perspicua (pars) Gould, Binney’s ed., p. 337, fig. 607 (?). 
Marsenina micromphala (Morch) Bergh, op. ult. cit., p. 121, 1857. 
G. O. Sars, op. cit., p. 151, pl. 21, figs. 10 a—d. 
Marsenina glabra Verrill, Proc. U. S. Nat. Mus., iii, p. 373, 1880. 
PLATE XLII, FIGURES 1, la, 4. 
This species is not’ uncommon at Eastport, Me., where I collected 

* There is a small, deep-water variety of DL. heros, very common in our dredgings 
south of Martha’s Vineyard, which has the umbilicus larger and more open than in 
the ordinary form. Intermediate states also occur, 
