246 MANUAL OF THE MOLLUSCA. 
STRUTHIOLARIA, Lam. 
Etymology, struthio, an ostrich (-foot), from the form of its 
aperture. 
Type, S. straminea, Pl. LV., Fig. 6. 
Shell turreted ; whorls angular; aperture truncated in front ; 
columella yery oblique; outer lip prominent in 
the middle, reflected and thickened in the adult; 
inner lip callous, expanded; operculum claw- 
shaped, curved inwards, with a projection from 
the outer, concave edge (Fig. 101). 
Animal with an elongated muzzle? tentacles 
cylindrical; eye-pedicels short, adnate with the 
tentacles, externally; foot broad and short. 
Fig. 101. 
Operculum of (KGener.) 
Struthwolaria. Distribution, 5 species. Australia and New 
Zealand, where alone it occurs sub-fossil. 
FAMILY [VY.—MELANIADE. 
Shell spiral, turreted ; with a thick, dark epidermis ; aperture 
often channeled, or notched in front; outer lip acute ; operculum 
horny, spiral. The spire is often extensively eroded by the 
acidity of the water in which the animals live. 
Animal with a broad non-retractile muzzle ; tentacles distant, 
subulate; eyes on short stalks, united to the outer sides of the 
tentacles ; foot broad and short, angulated in front; mantle- 
margin fringed; tongue long and linear, with a median and 3 
lateral series of hooked multi-cuspid teeth. Often viviparous. 
Inhabiting fresh-water lakes and rivers throughout the warmer 
parts of the world. 
MELANIA, Lam. 
Ltymology, melania, blackness (from melas). 
Type, M. amarula. Pl. VII, Fig. 25. 
Synonyms, Thiara, Megerle. Pyrgula, Crist. 
Siell tarreted, apex acute (unless eroded); whorls orna- 
mented with strise or spines; aperture oval, pointed above; — 
outer lip sharp, sinuous; operculum subspiral. Pl. VIII., 
Fig. 25.* 
Distribution, 361 species. South Europe, India, Philippines, 
Pacific Islands. Distinct groups in the southern States of 
North America, 
