118 limnjEid.'e. 



232. Planorbis merguiensis, PluUppi. 



Flanoriis infr(/uiemis, Philippi ubi ? ; II. & T.,C. I. ])1. lol, figs. 5, 6 ; 

 Sowerby, Couch. Icon, xx, pi. II, sp. 85; Clessin, Conch.-Cab. 

 1886, p' 140, pi. 12, figs. 2G-28, & pi. 20, tig. 4. 



Sliell depressed, solid, striate, shining, pale liorn-colour or 

 brown ; deeply umbilicate, sliglitly concave above ; whorls 4, 

 rapidly and regularly increasing, rounded ; suture above deep, 

 umbilical suture only lightly impressed ; the last M'horl twice as 

 broad as the penultimate ; aperture broadly semilunate, oblique ; 

 labrum acute, thickened. 



Alt. 6, diam. 12 mm. 



Hah. Mergui (Coll. Dunlver legit Phil.) ; Cliybassa, Bengal 

 (var. major) (Coll. Dunker). 



Section QYRAULUS. 



G?//-«»/MS,Agassiz,Nouv. Mem. See. Helv. i, 1837 (Ilartmann, 1844). 

 Nautiluia, Stein, Sebnecken Berlin, 1850, p. 50. 



Type, Planorbis alius, Midler ; Europe. 



llanrje. World-wide. 



Shell small, compressed, paucispiral ; whorls rapidly iucreasing, 

 the last broadening towards the aperture ; aperture rather wide. 



233. Planorbis (Gyraulus) compressus {llutton). 



Plaiiorl/is {Gyratilus) compressus (llutton), J. .\. S. B. iii, p. 91 

 (no. 13), 93; Benson, J. A. S. B. v, p. 743 ; Martens, Mai. 

 Blfitt. iv, p. 213 ; H. & T., C. I. pi. 99, figs. 1,4; Sowerby, in 

 fieeve. Conch. Icon, xx, pi. 14, fiff. 118 ; Clessin, in Conch.-Cab. 

 1886, p. 107, pi. 16, fig. 10. 



Planorbis tondanensis, Mouss.,Moll. Java, p. 44, pi. 5, fig. 4. 



Shell compressed, rather broad, pale, smooth, dextral, narrowed 

 above, broad below, somewhat keeled, spire depressed ; aperture 

 obliquely pyramidal, angular above, lower margin produced. 

 (Soiverb)/ in Reeve.) 



Alt. 3-5, diam. niaj. 11-5 mm. (iig. 118 rf. in Conch. Icon.). 



Ilab. Eiver Ganges, etc. 



234. Planorbis (Gyraulus) convexiusculus (ffutton). 



Planorbis {Gyraulus) convexiusculus (Hiitton), J. A. S. B. xviii, 

 pt. 2 (1849), p. 657 ; H. &. T., C. I. pi. 99, figs. 8-10 ; Sowerby, 

 in Reeve, Conch. Icon, xx, pi. II, sp. 9.3; Clessin, Conch.-Cab. 

 1884, p. 127, pi. 17, fig. 9. 



Orvjiiad description : — Shell depressed, ^ of an inch in diameter ; 

 pale horn-colour ; polished; closely and obliquely striate ; whorls 

 4 or 5 ; rounded ; suture well defined ; peripheiw subangular. but 



