240 LIMNJSAD^. 



This is proved by the size he gives for Planorhis 

 complanatus. B-ossmasler has partly corrected this 

 error ; he truly considers the P. complanatus of Tur- 

 ton, as only a state of growth of P. marginatus. 



108. 6. Planoebis complanatus. Margined Coll 

 Shell. — Shell horn-colour, brown, semitrans- 

 parent, striolate, flat or a little concave above, 

 flattish, with a slight central concavity, be- 

 neath ; whorls rapidly enlarging, flat, and 

 strongly keeled above, ventricose and rounded 

 to the margin beneath, (t. 8. f. 87, 88. 90.) 



Helix planorbis. Linn. Syst. i. 1242. ; part Penn. B. Z. ii. 

 t. 83. f. 123.; Linn. Trans, viii. 188. t. 5. f. 13. — Planorbis 

 umbilicatus. Mliller, Verm. ii. 160.; Jeffreys, Linn. Trans. 

 xvi. 384. — Helix complanata. Linn. S. N. i. 1242.— Pla- 

 norbis marginatus. Drap. p. 45. t. 2. f. 11, 12. 15. ; Bossm. 

 Leon. ii. t. 2. f. 59. ; Brard, p. 152. t. 6. f. 5. ; Alder, Mag. 

 Zool. and Bot. ii. 112.; Turton, Man. ed. 1. 107. f. 87.; 

 Leach, Syn. Moll. 114. t. 2. f. 7, 8.; Forbes and Hanley, 

 B.M. iv. 155. t. 127. f. 1, 2. — Planorbis carinatus. Studer. 



— Planorbis complanatus. Flem. E. Ency. vii. 69., B. A. 

 278. ; Turton, Man. ed. 1. 108. and f. 88. (not 89. as cited). 



— Helix limbata. Da Costa, B. C. 63. t. 4. f. 10., t. 8. f. 8. 



— Planorbis lacustris. liagouin, H. Jour. i. 273. — Pla- 

 norbis carinatus, var. h. Drap. Tab. 46. 



Var. 1. Planorbis turgidus. Jeffreys, Linn. Trans, xvi. 384. 

 Var. 2. Helix rhombea. Forbes and Hanley,B.M. t. 127. f. 3.; 



Turton, Conch. Diet. — Planorbis rhombeus. Turton, Man. 



ed. 1. 108, f. 90. — Planorbis Sheppardi. Leacli, Syn. Moll. 



115., fide Cab. Brit. Mus. — Helix Draparnaudi. Sheppard, 



Linn. Trans, xiv. 158.; Cab. Brit. Mus. — Planorbis Dra- 



parnaldi. Jeffreys, Linn. T'rans. xvi. 306. — Planorbis de- 



formis. Lam. \'i. 154.? 

 Var. 3., entirely without any keel. Alder, Catal. 113. 

 Monstrosity, with the volutions elevated into a spiral cone, 



always dextral : Helix terebra. Tiu-tou, Diet. p. 62. f. 55. 



— Helix cochlea. Brown, Wern. T'rans. ii. t. 24. f. 10. 



In staernant waters and slow rivers. 



