108 LAND AND FRESH-WATER MOLLUSKS. 
without opacity ; upper surface smooth or slightly 
wrinkled ; whorls three and a half to four, rather - 
flattened above; body whorl much larger than 
that preceding it; sutures well defined, deep | 
and narrow ; umbilicus moderately large ; aper- 
ture oblique, crescent-shaped, broader than high ; 
diameter one-tenth to one-sixth of an inch. 
HB&LICELLA CRYSTALLINA—(the Crystalline Snail) 
(Pl. VII., fig. 58)—is common among moss, 
herbage, decaying leaves, and under stones in 
woods, pastures, and hedgerows. 
The shell is flattened, with the spire very 
slightly raised; colour white, or with a slight 
greenish tinge, very shining and transparent ; 
under surface without opacity; upper surface 
smooth or slightly wrinkled ; whorls four and a 
half to five, of gradual increase, the body whorl 
being but little larger than that preceding it; 
whorls flattened above; sutures well defined ; 
umbilicus very small; aperture not very oblique, 
crescent-shaped, about as broad as high; dia- 
meter from one-twelfth to one-eighth of an 
ich. | 
HELICELLA ExcavATA—(the Hacavated Snail) 
(Pl. VII., fig. 52).—The shell is depressed, ‘sub- 
globular ; colour that of darkish horn, shining _ 
and transparent ; under surface not obscured by - 
any white opacity ; upper surface strongly and: 
regularly striated, the striz being continued 
