246 LIMN^ADuE. 



113. I. S'EGMESTis A nitida. Glossy Segment Shell, 

 (t. 8. f. 99.) 



Planorbis nitidus. Mliller, ii. 163. 1774; Drap. p. 46. t. 2. 

 f. 17—19.; Turton,Mun. ed. 1. 116. f. 91. ; Pfeifer; I 82. 

 t. 4. f. 12, 13.; Rossm. Icon. ii. 15. t. 7. f. 114, 1*15. — He- 

 mithalamus lacustris. Leach, Mollusc, p. 137. — H. nitidus. 

 Leach, Ann. and Mag. N. II. xx. 269. — Nautilus lacustris. 

 Lightf. Phil. Trans, t. xxvi. (1786), t. 1. f. 1—7.; Mont. 

 p. 191. t. 6. f. 3.; Flem. E. Ency. vii, 86. — Helix lineata. 

 Walker, Test. M. R. t. 1. f. 28. i784. — Planorbis clausula- 

 tus. Ferussac, 1820; Potiez and Michaud, Gall, i 209.; 

 Desmoulins, Moll. Girond. n. 10. — Segmentina nitida. Flem. 

 Edin. Ency. xii. — Helix nitida. Gmel. S. N. 3624.— 

 Planorbis nautileus. Sturm, D. F. ; Kiclix, Moll. Brah. 66. 



— Segmentina lineata. Flem. Brit. Anim. 279., Treat. 

 MolCAnim. t. 7. f. 13.; Graij, Man. 271. t. 8. f. 99.— 

 Planorbis complanatus. Poirct, Prod. 93. (not Linn. Drap.) 

 — Planorbis lacustris. Forbes and Hanley, B. M. iv. 162. 

 t. 128. f, 123. — Segmentina lacustris. Swains. Malac. 338. 



— Planorbis lineatus. Jeffreys, Linn. Trans, xvi. 389. ; 

 Aide?; 114. 



In stagnant waters, on aquatic plants. 



Shell hardly a quarter of an inch in diameter, 

 highly polished and smooth, of a chestnut or reddish- 

 brown colour, flattish and semitransparent ; volutions 

 p. gg four, the outer one very large in pro- 

 portion, and marked wdtli two or three 

 whitish transverse lines exhibiting the 

 internal partitions ; the upper surface very convex, 

 with a deep umbilicus in the centre, the under side 

 nearly flat, and umbilicate in the centre ; the circum- 

 ference slightly carinate ; aperture oval, inclining to 

 triangular, with the peristome interrupted. 



Except for its internal semiconcamerated partition, 

 this shell exactly resembles the Planorbis fontanus, 

 but is larger. 





