A. E. Verrill— Catalogue of Marine Mollusca. 481 
Variety, tenuicostata. 
? Bela tenuicostata G. O. Sars. op. cit.. p. 237, pl. 17, figs. 1 a. 6, pl. ix, fig. 6 (den- 
tition), 1878. 
Bela tenuicostata (pars) Verrill, Amer. Journ. Sci., xx, p. 391, Nov., 1880. 
Verrill, Proc. U. S. Nat. Mus., iii, p. 365, 1880. 
This is closely related to 5. decussata Couth., of which it is, per- 
haps, only a variety. It has smaller and more numerons ribs, and is, 
therefore, more finely and uniformly cancellated. It agrees with B. 
decussuta very closely in size and form and in the flexuous character 
of the ribs. 
Specimens apparently identical with this form were dredged by me, 
in moderate depths, at Eastport, Me., in 1864, 1868 and 1870. I am 
inclined to believe that these American examples, at least, are noth- 
ing more than a variety of B: decussata, with unusually regular and 
finely decussated sculpture. 
Variety, pusilla, nov. 
A small variety of this species occurs in which the ribs are less 
prominent and not so much bent at the shoulder, giving the shell a 
smoother appearance. In form of the whorls and aperture, and in 
the spiral cinguli it agrees with the ordinary form. It resembles the 
European 4. Trevelyana, but is shorter and less decidedly cancel- 
lated. 
This was taken in Casco Bay, 12 to 15 fathoms; Halifax harbor, 
18 fathoms. 
Bela decussata is a well-characterized species, but has, undoubt- 
edly, been confounded with other species, especially with B. ineisula 
V., which it resembles in size and somewhat in form, but from which 
it differs very decidedly in sculpture, and in lacking the angular 
shoulder of that species. 
When eroded, small specimens are liable to be mistaken for B. 
hicarinata, or its variety, violacea, but it is generally stouter in form, 
with a shorter spire, and lacks the raised cinguli, usually seen in the 
latter. 
Bela bicarinata (Couth.) Verrill. 
Pleurotoma bicarinata Couthouy, Boston Journ. Nat. Hist.. ii, p. 104, pl. 1. fig. 
|W beads 
Gould, Invertebrata Massachusetts. ed. i, p. 281, fig. 186, 1841; ed. ii. p. 349. 
fig. 618. 
Verrill, Report Invert. Vineyard Sd., p. 638 [344], pl. 21, fig. 106, (after Gould). 
Mangelia bicarinata Stimpson, Shells of New England, p. 49, 1851. 
Defrancia bicarinata A. and A. Adams, Genera Recent Mollusca, i, p. 95, 1858. 
Bela bicarinata G. O. Sars, Mollusca Arctice Norvegiz. p. 237, pl. 16. figs. 11, 12, 
pl. ix, fig. 7, (dentition), 1878. 
