A. E. Verrill—Mollusca of the New England Coast. 187 
ceals; both above and below this, at about equal distances, there is 
another less prominent carina, the lower one defining the basal area; 
the upper one is about midway between the median carina and the 
suture. The intervals between these carinze are broadly concave 
and crossed by numerous pretty regularly spaced, thin, raised and 
curved riblets; those between the upper carina and the suture have 
their concave side toward the aperture and terminate posteriorly in 
-a small, shghtly prominent lobe or crest in crossing the sutural 
carina; those in the two peripheral zones have their convex side 
toward the aperture and do not cross the carine. On the base there 
are about seven to nine rather prominent revolving cinguli, besides 
the carina already referred to; the intervals between these are con- 
cave and variable in width, and are crossed by numerous, small, 
oblique riblets. The surface of the whorls between the riblets is 
covered by fine revolving lines, visible with a lens. The umbilicus 
is represented only by a narrow spiral groove or channel, nearly 
concealed by the strongly recurved or reflected margin of the colu- 
mella-lip, and bounded outwardly by a spiral ridge. The aperture 
is rather large and angulated, or lobed, with a deep, rather broad 
posterior sinus, which is deepest just above the upper carina, where 
the corresponding riblets are most strongly excurved ; below this the 
outer lip is thin, and bends outward and inward, corresponding to 
the external carine and their interspaces; below the periphery and 
opposite the most convex part of the base the outer lip bends out- 
ward and shows another shallow sinus; there is also a small sinus or 
rudimentary canal at the junction of the lip with the extremity of 
the columella, which terminates in a small, somewhat prominent 
angle. The columella-margin is strongly spirally twisted, much 
excurved opposite the umbilical region, beyond which it curves 
strongly forward and outward, forming there a small, prominent, 
sometimes slender tooth, which is often broken. The operculum is 
ear-shaped or broad-ovate, with an emargination on one side, thin, 
translucent, pale yellow, with a very delicate, concentric structure. 
The nucleus is sub-central; around it are numerous thin, close, con- 
centric lines, most distinct about midway between the center and 
margin; the outer part is transparent and shows no distinct lines ; 
the muscular attachment is ovate, not very large, and excentric to 
the center. 
Jaws thin, brown, irregularly ovate, the outer half covered with 
small tesselated elevations, becoming more prominent, blunt or 
spatuate at the margin. 
TRANS. Conn. AcaAD., VOL, VI, 24 May 26, 1884, 
