242 SNAILS AND SLUGS [CH. VII 



(Helicella Fer.) itala (L.), f", shell depressed, greyish with 

 brown bands, aperture nearly circular, umbilicus large. Dry 

 downs with short turfs. 



* (Helicodonta (Fer.) Risso.) obvoluta (Hull.), ", shell depressed, 



rufous brown, aperture triangular and toothed, umbilicus 



large. 



( Vallonia Risso.) pulchella (Hull), T V, shell milky- white. 

 (Hygromia) fusca (Mont.), J", shell wrinkled. 



* revelata (Fer.), ", greenish, bristly, transparent ; umbilicus large. 

 (Acanthinula Beck.) aculeata (Hull.), -f", periostracum raised, 



whorls 4 to 4^, aperture semicircular. 

 lamellata (Jeff.), f", periostracum raised, whorls 6, aperture 



crescentic. 



(Cochlicella (Fer.) Risso.) barbara (L.) = acuta (Hull.), f", whorls 

 8 or 9 ; shell long and spiral, aperture oval, umbilicus small. 

 Endodontidse Pilsbry. 



(Punctum Morse.) pygmcea (Drap.), ^y, shell pale horn-coloured. 

 (Sphyradium Charp.) edentulum (Drap.), -fa" vertigo edentula, 



shell faintly striated. 

 (Pyramidula Fitz.) rupestris (Drap.), ", shell blackish -brown. 



rotundata (Hull.), J", shell bluntly keeled. 



An enormous number of varieties have been described, especially 

 of nemoralis, hortensis, and arbustorum. 



Family SUCCINEID^E. Shell oval or oblong, thin ; spire short, last 

 whorl large, mouth obliquely oval ; tentacles four, retractile. 

 Aquatic or semi-aquatic, on stalks and leaves of water plants, 

 generally above the surface, 

 genus Sucdnea Drap. 

 oblonga Drap., |", light horn-coloured, whorls 4, suture oblique, 



very deep. 

 elegans Risso, f", oblong amber-coloured, or greenish-yellow, 



whorls 3 or 4, suture very oblique but not deep. 

 putris (L.), f", oval, whorls 3 or 4, mouth oval and | length of 

 shell, suture rather oblique and very deep. 



Family STENOGYRID/E. Shell long, cylindrical, thin, translucent ; 

 spire long, whorls rapidly increasing in size, aperture notched. 



* Occur only in southern and western counties. 



