Mollusca of Great Britain. 383 



Planorbis contortus. Mull. Verm. 2. p. 162. Drop. 



Hist, des Moll. p. 4>^. t.l.f. 39 — 41. 

 Helix contorta. Linn. Syst. Nat. 1. p. 1244. 



In ditches, &c. ; but more local than the last. 

 ** Anfractibus paucis. 



3. CORNEUS. 



Animal nigrum. Tentacula longa, curvata, sordid^ cinerea. 



(Milll.) 

 Testa supr^ concava, perforata, subtiis plana, subumbili- 



cata, tenuis, substriata, castaneo-fusca seu cornea. 



Anfr actus 6, extiis rotundati. Apertwa subdilatata : 



peristomio reflexiusculo. 



Long. 0.45. — Diam. 1.25 ferh. 



Planorbis corneus. Drap. Hist, des Moll. p. 43. t. 1. 

 f. 42—44. 



Purpura. Miill. Verm. 2. p. 154. 



Helix cornea. Linn. Syst. Nat. 1. p. 1243. 



In slow rivers and large pools of the midland counties of 

 England. 



4. TURGIDUS. 



Animal 



Testa supr^ planiuscula, subtiis plana, lateribus inaequa- 

 lissimis, utrinque subumbilicata, fragilis, hyalina, 

 substriata, sordid^ alba. Anfr actus 6, subangulati. 

 Apertura inaequalis. 



Long. 0.2. — Diam. 0.55. 



Planorbis albus. Shroter Flussconch. t. 5.f. 28. 

 Helix turgida. Gmel. Syst. Nat. 1. p. 3641. 

 VOL. XVI. 3d a single 



