A. E. Merrill — Catalogue of Marine Mollusca. 
483 
The nucleus is prominent, the apical whorl is distinctly raised and 
a little incurved, nearly smooth, pale; on the second whorl two spiral 
carinse appear, and on the third these become strong and are crossed 
by riblets. Slight, but distinct, nearly straight ribs are often present 
on the upper whorls, below the shoulder. 
Aperture small, narrow-elliptical ; outer lip with a well-marked, con- 
cave posterior sinus, below which it projects forward and is broadly 
rounded, and is scarcely incurved at the base of the canal, which is 
very short, straight, and open, truncate at the tip. Columella deci- 
dedly excavated in the middle. 
Color, when fresh, commonly deep chestnut-brown, varying to pale 
chestnut, sometimes more or less violaceous brown ; the canal and 
columella are usually pale. 
Variety, violacea (Mighels and Adams). 
This differs from the typical form only in being a little larger and 
stouter and in having the two carinse on the upper whorls somewhat 
less evident (partly owing to erosion). The variety is connected 
with the typical form by intermediate specimens of every degree. 
I have collected numerous specimens of this form in Portland har- 
bor, at the precise spot where it was first found by Dr. Mighels, in 
1841, and have them now before me. They belong to the stouter and 
smoother form of this species, of rather large size, dark colored, with 
a slightly bluish tint, and all have the upper whorls more or less 
eroded, so as to appear smoother than is natural. 
As a general fact, it may be said that the young of this species, 
when perfect, have been classed as B. bicarinata , while the adult, 
or eroded young, have been named B. violacea by conchologists. 
The uncini of the two forms, as figured by G. O. Sars, do not essen- 
tially differ. 
An adult specimen, with seven whorls, form violacea , is ll mm long; 
breadth, 5 mm ; length of body-whorl with canal, 7 mra ; breadth, 4’2 mm ; 
length of aperture, 5"“'"; its breadth, 2 11 "". A specimen of the typi- 
cal form is 8 o nini long; breadth, 3 , 75'" m ; length of aperture, 4""" ; its 
breadth, P5"" 11 . 
This species has a very extensive distribution. On our coast it is 
found from Cape Cod to Labrador! And in depth, from just below 
low-water mark to 110 fathoms! Greenland, 5 to 57 fathoms, — Jeff- 
reys; Spitsbergen, — Torell and others; Iceland, — Morch and others; 
Norway, — G. O. Sars; nort h of Hebrides and west of Ireland, 170 to 
420 fathoms, Lightning and Porcupine Expeditions, — Jeffreys. 
Trans. Conn. Acad., Vou V. 58 June, 1882. 
