162 limntead^. 



Dorset Catal. p. 53, pi. 19, f. 19.— Dill w. Recent Shells, 



vol. ii. p. 898.— Wood, Index Testae, pi. 33, f. 95. 



Planorbis complanatus, Drap. Moll. Ter. et Fluv. France, p. 47, pi. 2, f. 20. — 



Brard, Coq. Envir. Paris, p. 161, pi. 6, f. 4.— C. 



Pfeif. Deutsch. Land und Silssw. Moll. pt. 1, p. 83, 



pi. 4, f. 14. — RossmASSL. Iconog. Land und S'ussw. 



Moll. pt. 2, p. 16, pi. 7, f. 116 Gras, Moll. Ter. et 



Fluv. France, p. 59, pi. 4, f. 40. 

 Helix lenticularis, Alten, Conch. Augsburg, p. 35, pi. 2, f. 4. 



Planorbis lenticularis, Kickx, Moll. Brabant, p. 67 Hartm. in Sturm Deutsch. 



Fauna, sect. 6, pt. 7, pi. 16; Erd und Sussw. Moll, 

 pi. 13 (Hippeutis). 

 „ fontanus, Turt. Manual L. and F. W. Shells, p. 110, f. 93. — Stein. 

 Schnecken Berlins, pi. 2, f. 22. 



Shell most closely resembling lacustris, but still more 

 depressed, less polished, usually paler, being horn-coloured, 

 and perfectly devoid of the internal partitions and their 

 corresponding external indications. Whorls of the spire 

 more convex; the apical one more distinct, and less sunken. 

 Keel slightly more central. Mouth nearly filling three- 

 sevenths of the total width, still more compressed than in 

 lacustris. 



Animal, when adult, brownish black, paler about the 

 tentacula ; when young, pale grey. 



Generally distributed through England, and the south of 

 Scotland; wide spread, but local, in Ireland. 



P. lacustris, Lightfoot. 



Highly polished, amber-coloured, with internal partitions : 

 periphery angulated. 



Plate CXXVIII. figs. 1,2,3. 



Helix complanatus, Linn. Syst. Nat. ed. 12, p. 1242 (inadequately described). 



Planorbis nitidus, Miller, Hist. Verm. vol. ii. p. 163, in part. — Turt. Manual 

 L. and F. W. Shells, p. 116, f. 9.0. — Drap. Moll. Ter. et 

 Fluv. France, p. 46, pi. 2, f. 17, 18, 19.— C. Pfkif. Deutsch. 



Land und Sussw. Moll. pt. 1, p. 82, pi. 4, f. 12, 13 Nils. 



Moll. Suec. Ter. et Fluv. p. 82. — Hartm. Sturm Deutsch. 

 Fauna, sect. 16, pt. 7, pi. 15. — ROSSMASSL. Iconog. Land 

 und S'ussw. Moll. pt. 2, p. 1 5, pi. 7, f. 1 14, 1 15. — Boi/illet, 



