A . K. VerriM — Cataloyw of j\fariue Atoll u.sca . 48 1 
Variety, tenuicostata. 
? Bela tenuicostata G. 0. Sars, op. eit.. p. 237. pi. 17. tigs. 1 a, b. pi. ix. fig. 6 (deu- 
tition), 1878. 
Bela tenuicostata, (pars) Terrill, Amer. Jouro. Sci.. xx. p. 391, Nov., 1880. 
Terrill, Proc. 1 T . S. Nat. Mus.. iii. p. 365, 1880. 
This is closely related to B. decussata Couth., of which it is, per- 
haps, only a variety. It has smaller and more numerous ribs, and is, 
therefore, more finely and uniformly cancellated. It agrees with B. 
decussata very closely in size and form and in the fiexuous 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, pus ilia, now 
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 B. 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. incisula 
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. 
hi car mat a , 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 hi carina ta (Couth.) Verrill. 
Pleurotoma bicarinata Couthouy, Boston Journ. Nat. Hist., ii. p. 104. pi. 1. fig. 
11, 1839. 
Gould. Fnvertebrata Massachusetts, ed. i. p. 281. fig. 186. 1841; ed. ii. p. 349. 
fig. 618. 
Verrill, Report Invert. Vineyard Sd., p. 638 1344). pi. 21. fig. 106. (after Gould). 
Mangelia bicarinata Stimpson. Shells of New England, p. 49. 1851. 
Befmncia bicarinata H. and A. Adams. Genera Reeent Mollusca. i. p. 95, 1 85s. 
Bela bicarinata G. O. Sars, Mollu9ca Arcticae Norvegiw. p. 237. pi. 16. figs. 11. 12, 
pi. Lx, fig. 7, (dentition). 1878. 
