196 MOLLUSCA. 
crossed by fine revolving striz, so as to give the surface a decussated 
appearance ; whorls eight, convex, slightly shouldered posteriorly, the 
last one half the length of the shell; suture well defined; aperture 
ovate, subtruncate at base; lip simple; columella arcuated and fur- 
nished at its lower portion with a broad, compressed, concave tooth ; 
umbilical pit large and distinct, bounded externally by a somewhat 
prominent ridge; interior of a lighter shade of brown. 
Length of axis three-fortieths of an inch; breadth one-fortieth. 
Found on a floating bamboo, lat. 37° 40’ N., long. 54° 30’ W. 
[aR Call 
Three other species of this genus have been noticed, namely, L. 
melanostoma, Rang, which has the lip black; L. maculata, Rang, 
which has two brown spots on each whorl; and L. striata, Pfeiffer, 
with which this agrees well, except that it is less than half the size. 
Figure 232, front view of the shell, magnified ; 232@, natural size. 
SoLaRtumM EGENUM (Gould). 
Testa parva, ovato-conica, exalbida, submargaritacea : spira anfractibus 
sex convexis, lirts acutis quatuor cinctis, posterioribus granulatis : 
basis convexiuscula, perforata; umlilico scalariformi, ad amlitum 
acuto, crenulato: apertura circularis ; labis feré continurs. 
Solarium egenum, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 84. 
March 1849. Expedition Shells, 54. 
SHELL minute, low ovate-conic, thin, amply umbilicated, ashy- 
white, pearly beneath ; whorls six, convex, the last obtusely angular, 
each one encircled by four sharply-compressed, well-elevated ribs, 
the two uppermost of which are beaded ; interspaces concave, smooth ; 
base convex, smooth, with a single groove near the margin of the 
umbilicus; the latter occupies one-third of the base, is tunnel-shaped, 
penetrating to the apex, its sides excavated on each whorl, the verge 
of which is crenulated: aperture nearly circular, slightly encroached 
upon by an inflection of the columella; lip simple : interior pearly. 
