UNIVALVES. — HELIX. 127 



Of the turreted or tapering Helices may be particula- 

 rized the H. decollata and H. columna. 



The last division contains those species which have their 

 apertures very large, exposing the whole of the interior of the 

 shell, and bear in shape a strong resemblance to the genus 

 Haliotis; of these the H. haliotoidea may be adduced as 

 an example. 



Many of the Helices inhabit aquatic plants in standing 

 waters, lakes, ponds, and ditches : others are found on trees 

 and shrubs, and some harbour among rotten wood. 



UEUX—SnaiL 



Division I.— Shell with a carinated margin on the 



BODY-WHIRL. 



Family 1. — UmbiUcated and depressed. 



*Lapicida — Roch. Exilis — White-striped. 



Marginata — Margined, *Cantiana — Kent. 



Cicatricosa — Reversed. *Rufescens — Reddish. 



Albella — Whitish. *Crenulata — Black-tipp'd. 



Albina — Minute-white. Annulata — Ringed. 



*Rotundata — Small-radiated. *Fontana — Fresh-tvater. 



Laevipes — Reverse-whirl' d. Turcica — Turkish. 



Family 2. — UmbiUcated and convex. 



Cornu — Large-horn. Trochoides — Angular-mouth. 



Oculus-capri — Goat's-ei/e. Incarnata — Flesh-colour' d. 



Involvulus — White-reflected. Maculosa — Sjjotted. 



Striatula — Striated. Corrugata — Wrinkled. 



Algira — Yellowish. Pellis-serpentis — Snake' s-skin. 



Leucas — Purple- lined. Avellana — Hazel-nut. 



Family 3. — Imperforated and depressed. 

 Lampas — Orange -lip. Gualteriana — Gualter's. 



Carocolla — Large- brown. Faba — Bean-shap'd. 



