ORDER PECTINIBRANCHIATA. 65 
generally the columella is not dentated. It inhabits fresh 
water. 
A small species, very prettily coloured, abounds in the 
rivers of France; it is the Nerita fluviatilis, L., Chemn. IX. 
exxiy. 188. Add Nerita turrita, Chemn. 
The columella in others, however, is finely crenulated 
(Nerita pulligera, Chemn.), and of this number there are 
some in which the spire is armed with long spines. (CLITHON, 
Mont.; Nerita corona, Chemn.) 
According to our recent investigations, it is to the trochoida 
that we must approximate a family, which we shall call 
CAPULOIDA, 
And which comprehends five genera, four of which have been 
dismembered from the patelle: they all have a widely 
opened, scarcely turbinated shell, with neither operculum, 
emargination, nor siphon. The animal resembles the other 
pectinibranchiata, and has the sexes separate. There is but 
one branchial comb, transversely arranged on the roof of the 
cavity, and its filaments are frequently very long. 
CAPULUS, Mont. PiLEopts, Lam. 
A conical shell, with a recurved and spiral summit, which 
has long caused it to be placed with the patelle ; the gills are 
in one range, under the anterior margin of the branchial cavity ; 
the proboscis is long, and there is a closely-plaited membran- 
ous veil under the neck; the eyes are at the external base of 
the conical tentacula. (Patella Hungarica, List. 544. 32.) 
Htpronyx, Def/r., 
Would appear from the shell to be a fossil capulus, very re- 
markable, however, for a bed formed of calcareous matter, on 
which it rests, and which probably exuded from the foot of 
the animal. (Putella cornucopie, Lam.) 
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