GASTEROPODA. 308 
Shell obtusely cone-shaped, smooth ; spire short, flat-whorled ; 
aperture long, narrow; lip sharp, denticulated within; colu- 
mella twisted in frout; wall of the aperture with 1 or 2 spiral 
plaits. 
Animal with short, tapering, and rather compressed tentacles ; 
foot divided transyersely into two portions, advanced successively 
in walking. 
Distribution, 56 species. West Indies, Europe. In salt- 
marshes and on the sea-shore. The British species have thin 
ovate shells, with the spire moderately produced, and the aper- 
ture oval. They form the sub-genus Alexia (denticulata), 
Leach. 
Fossil, Eocene. Britain, France. 
CARYCHIUM, Miller 
Type, C. minimum, Pl. XII., Fig. 39. 
Synonym, Auricella, Hartm. 
Shell minute, oblong, finely striated transverse1y; aperture 
oval, toothed, margin thickened, united by callus. 
Animal, with 2 blunt, cylindrical tentacles; eyes black, 
sessile, near together, behind the tentacles. 
Distribution, 9 species. Europe; North America. At the 
roots of grass in damp places, especially near the sea. 
Fossil, 3 species. Miocene—. Europe. 
The genus Siphonaria, described at p. 281, is supposed to be 
pulmoniferous, and to bear somewhat the same relation to 
Auricula that Ancylus does to Limnaea. The lingual dentition 
is similar to Auricula; the centre teeth are distinct, the laterals 
numerous and hooked. 
My a 
27) 
"ap She wea 
ee Y, ; y ASS 6 
72) AAS 
oy 
“mh, pappraaTatnannnen es! 
Day, VOLITION a 
OLIN PRE 
Fig. 133.4 
SEcTION B.—OPERCULATA.t 
The Operculated land-snails are exceedingly like periwinkles 
* Siphonaria species from the Cape; three rows of teeth, c central, 7 laterals, from 2 
preparation by J. W. Wilton, Esq., of Gloucester. 
+ Phanera-pneumona (open-lunged), Gray. The account of this group is chiefly 
tuken from the catalogue prepared by my friend Dr. Baird. 
