71 
Lengthy about 4-6 incli. Inhabits Ohio River. 
Found in plenty at the falls of the Ohio. The spire is remarkably 
carious in the older shells^ and the penultimate whirl, between the 
aperture and the spire, is also remarkably eroded in many older 
shells. The spire in the young shell is entire, and but little promi- 
nent, though acute, and the bands are distinct on the exterior of 
the shell. This shell does not seem to correspond with the genus 
to which I have, for the present, referred it ; and owing to the 
configuration of the base of the columella, if it is not a Melau'opsis^ 
it is probable its station will be between the genera Melanm and 
AcatJiina. I propose for it the generic name of Anculosa. 
Melania armigera. — ^Sheil tapering, brownish-horn color; 
volutions about six, slightly wrinkled ; spire near the apex eroded, 
whitish ; body whirl with a revolving series of about five or six dis- 
tant, prominent tubercles, which become obsolete on the spire, and 
are concealed by the revolution of the succeeding whirls, in conse- 
quence of which arrangement there is the appearance of a second, 
smaller, and more obtuse subsutural series of tubercles on the body 
whirl ; two or three obsolete, revolving, reddish-brown lines ; aper., 
ture bluish-white within ; a distinct sinus at the base of the colu- 
mella. 
Inhabits Ohio River. Length about one inch. 
Distinguished from other N. American species, by the armature 
of tubercles. 
Bulla fluviatilis. — Shell suboval, pellucid, pale yellowish 
white, finely wrinkled ; volutions three ; body whirl large, with a 
prominently carinated shoulder bounding the spire ; spire perfectly 
flat or slightly concave, giving to the shell a perfectly truncated 
appearance in that part ; aperture longer than the columella, ob- 
long-ovate, extending beyond the tip of the spire ; umbilicus pro- 
found, edged by a slight carina. 
Length of the aperture one-fifth of an inch. Greatest breadth 
somewhat less. Inhabits the River Delaware. 
This species seems to be rather rare ; it was discovered by Mr. 
Aaron Stone, deeply imbedded in the mud ; Mr, William Hyde, of 
this city, has since found specimens of it amongst some dead sheiks 
of other genera assembled in a small inlet of the river. 
