182 CONTRIBUTIONS 
GENUS OLIVA. Lamarck. 
O. constricta. Plate 6. Fig. 195. 
Description. Shell cylindrico-fusiform ; substance of the 
shell rather thick; spire elevated, pointed ; whorls six, flat 
above ; columella with about five irregular folds near the 
base ; mouth narrow, about three fifths the length of the 
shell. 
Length .9, Breadth .3, of an inch. 
Observations. There is a great resemblance between 
this species and the clavula (Lamarck), and it may be 
doubtful if they should be separated. Our shell has a 
shorter mouth, a higher spire, and is, perhaps, more 
slender. 
O. gracilis. Plate 6. Fig. 196. 
Description. Shell subfusiform, polished ; substance of 
the shell thin ; spire elevated, pointed ; whorls five, slightly 
convex ; columella with five or six irregular folds near the 
base ; mouth narrow, about one half the length of the shell. 
Length 7-20ths, Breadth .1,of an inch. 
Observations. The graceful form of this little species, as 
well as its size, will easily distinguish it from the following 
one. It is less cylindrical than that which precedes it, 
and properly placed between both, as it bears some of the 
charactere af hath 
