188 
AURICULID^. 
Dr. Turton calls C. parvula (t. 5. f. 59.) ; and also the 
specimens of the true C. parvula (according to Fe- 
russac) found in Germany, for comparison.” He 
further observes that all the British specimens he 
has seen, he thinks, are only varieties of (7. nigricans^ 
which, I think, the specimen fully bears out. 
Sub-order III. Limnophila. 
Eyes sessile ; tentacles two, subcylindrical or 
flattened, simply contractile ; operculum none. The 
organs of generation with separate external open- 
ings sometimes close together. Fluviatile. 
The male and female organs of these animals are 
more distinctly developed ; in this respect they ap- 
pear to be intermediate between the hermaphrodite 
Geophila and the unisexual Gasteropods. 
Earn. 4. AUKICULID^. 
The animal with an elongated foot, an elongate 
ringed muzzle, two subcylindrical tentacles, with 
the eyes near the inner hinder side of their 
base ; body spiral, placed on the centre of the 
foot, and covered with a thin mantle with a 
thickened edge, which is itself covered with an 
external spiral shell, which has a plaited pillar in 
all its ages. 
These Mollusca appear, by habit and character, 
to be exactly intermediate between the land and 
