114 GASTEROPODA. LIMNADZ. 
round London and Eton; near Lackham, in Wiltshire; and 
about Bristol and Bath. 
3. PLANORBIS CARINATUS. 
P. testa corned, pellucida; anfractibus transversim striatis, ad 
medium dorsi carinatis. 
Planorbis carinatus, Mill. Verm. Hist. 157, 344; Drap. Hist. 
des Moll. 46. pl. 2. figs. 13, 14, 16; Flem. Edinb. Encycl. 
vil. 69. 
Helix carinata, Mont. Test. Brit. 450. t. 25. fig. 1. 
Helix planata, M. §& R. Trans. Linn. Soc. vii. 189. 
Helix planorbis, Turt. Conch. Dict. 45. 
Animal olivaceum. Tentacula et margines pedis crocei vel 
testacel. Oculi nigri. 
Habitat in stagnis, paludibus, et in aquis lenté fluentibus. 
Shell horny, pellucid ; the whorls transversely striated, cari- 
nated in the middle of their dorsal aspect. Diameter five- 
eighths of an inch. 
Animal olivaceous. Tentacula and margins of the foot saf- 
fron or testaceous. Eyes sooty-black. 
The left side of the whorls is decidedly less convex than the 
right side. It may always be recognized by the appearance of 
the keel, when viewed in front of the aperture. 
Inhabits ditches, ponds, and slowly flowing waters. It is 
common around London and Cambridge. It occurs likewise 
in ditches, round Wareham, in Dorsetshire, and Eton; and to 
the east of Edinburgh, in similar situations. 
4. PLANORBIS MARGINATUS. PI. ITI. figs. 7, 8. 
P. testa, corned, fusca, subpellucida, ad sinistram planiore ; 
anfractibus transversim striolatis, ad sinistram dorsi cari- 
natis. 
Helix Planorbis, Linn. Syst. Nat. 1. 1242; Penn. Brit. Zool. 
iv. 1383; M. & R. Trans. Linn. Soc. viii. 188, t. 5. fig. 13. 
Planorbis umbilicatus, Mill. Verm. Hist. 349, 160. 
Helix complanata, Mont. Test. Brit. 450; Dill. Desc. Cat. 
897; Turt. Conch. Dict. 46. 
