35 
M E L A NO PS IS . Lamarck. 
Gen. Char. Univalve, subfusiform or limited ; 
mouth oval, pointed above, emarginate be- 
low ; outer lip sharp edged, entire, upper 
part pressed against the spire ; inner lip 
thick, tumid above ; columella plain, acute, 
curved ; operculum coriacious. 
A genus of Fresh water shells lately established, and 
of which there are several recent species ; the lower part 
of the mouth in some of them is produced into a very 
short beak, and in all it is more or less dilated ; the epi- 
dermis is rather thick smooth, and generally of a black- 
ish green colour, as in most fresh water genera ; the 
animal closes the mouth of its shell with a coriacious 
operculum, that increases from a point situated near the 
lower part of its inner edge ; it is rather partial to tem- 
perate climates. 
MELANOPSIS fusiformis. 
TAB. CCCXXXII.— Figs. 1 to U 
Spec. Char, Fusiform, in the middle subcylin- 
drical, smooth ; mouth half the length of the 
shell. 
This species is liable to considerable variation in length* 
some specimens being much elongated, others ovate 
and pointed. The shorter ones have most of the subcy- 
lindrical form of Ancilla, and also a slight sinus towards 
the upper part of the outer lip, where it is applied to the 
opposed callus, which is largest in such individuals* 
Since there is a series of these forms found in the same 
place, and as the mouth is constantly hah as long as the 
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