Mollusca of Great Britain. 383 
Planorbis contortus. Müll. Verm.2. p.162. Drap. 
Hist. des Moll. p. 42. t. 1. f. 39—44. 
Helix contorta. Linn. Syst. Nat. 1. p. 1244. 
In ditches, &c. ; but more local than the last. 
** Anfractibus paucis. 
3. ConNEvs. | 
Animal nigrum. Tentacula longa, curvata, sordidé cinerea. 
( Müll.) 
Testa suprà concava, perforata, subtis plana, subumbili- 
cata, tenuis, substriata, castaneo-fusca seu cornea. 
Anfractus 6, extus rotundati. Apertura subdilatata : 
peristomio reflexiusculo. 
Long. 0.45.—Diam. 1.25 feré. 
Planorbis corneus. Drap. Hist. des Moll. p. 43. t. 1. 
f. 49—44. 
Purpura. Müll. 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 suprà planiuscula, subtis plana, lateribus ipeque- 
lissimis, utrinque - bulis, frag " 
Rees inzqualis. | m : 
Long. 0. T —Dism. 0. 55. 
Planorbis albus. Shroter Flussconch. t. 5. f. 28. 
Helix turgida. Gmel. Syst. Nat. 1. p. 3684 T. 
VOL. XVI. 3D TN, Page 
