164 LAND AND FRESH-WATER MOLLUSKS. 
narrow and triangular, in consequence of the 
great contraction of its outer edge in the middle. 
It is found about the roots of grass in marshy 
places in a few localities :—Singleton, near Swan¬ 
sea ; Tenby; rejectamenta of the river Avon, at 
Bristol; Battersea; in Ireland, at Miltown Malby, 
co. Clare; Connemara, Galway; and at Cork. 
It occurs in Central Europe. 
Genus Balea. 
The animal is bulimus-like ; the lingual ribbon 
is furnished with 130 rows of teeth, each row 
containing 50. The shell is thin, slender, elon¬ 
gated, of many reversed whorls; the aperture is 
ovate, with the peristome thin, and sometimes 
furnished with an imperfect fold on the columella. 
The genus is intermediate between Pupa and 
Clausilia , but differs from the former in the 
shape of the aperture and the elongated spire, 
and from the latter in having no clausium. 
This generic group contains only a few species, 
one of which is indigenous to this country:— 
Balea perversa— {the Fragile Moss Shell ) (PI. 
IX., fig. 86).—The shell is oblong, slender, 
yellowish, transversely striated with seven or 
eight distinct whorls ; the aperture is roundish, 
oval, and reversed; the peristome is thin, and a 
little reflected on the columella, where there may 
