802 CLASS XIII. 



Sp. Ampullaria fasciata LAM., Helix ampullacea L., HUMPH. Ami. Rariteitk. 

 Tab. 27, fig. Q, Encycl. mtth., Vers. PL 457, figs. 3, A, B, &c. Fresh-water 

 molluscs of tropical countries, much allied to Paludina and Cyclostoma 

 See F. H. TROSCHEL Anatomie von Ampullaria urceus und ueber die Oat- 

 tung Lanistes MONTF. in ERICHSON'S Archiv f. Naturgesch. 1845, s. 197 

 116, Taf. 8. To Ampullaria belongs also Planorbis Cornu Arietis LAM. 



Planaxis LAM. 



Sp. Planaxis sulcata LAM., BLAINV. Malacol. PI. 16, fig. 14. 



Eissoa FREMINV. Shell mostly turrite, sometimes globose, 

 with oval aperture, labrum incrassate, exsert anteriorly and sub- 

 arcuate near the columella, the apex acuminate. Operculum 

 horny. Tentacles elongate. Eyes placed at the base of tenta- 

 cles. Foot oblong, anteriorly truncated, posteriorly acuminate. 



This genus consists of small marine animals, whose little shell has some 

 resemblance to Turbo or Scalaria, and of which the numerous species have 

 become known in the last few years alone; there are also many fossil 

 species, almost all from the tertiary formations. Compare DESHAYES in 

 LAMARCK Hist. not. des Ani. s. vert. 2e eM. viu. pp. 461 485 ; J. ALDER 

 Ann. of Nat. Hist. xm. pp. 323 328; LOVEN Ind. Molluscor. ofversigt, 

 1846, pp. 2426. 



Melania Lam. Shell turrite, with apex often decorticated, 

 eroded. Aperture entire, ovate or oblong, effuse at the base. 

 Columella smooth. Operculum horny, elongate. Animal elon- 

 gate, with foot small, and two elongate filiform tentacles. 



Note. Genus Pirena LAM., Pyrena MENKE, GRAY is, according 

 to DESHAYES, to be abolished. Smooth and shining marine species 

 of Melania form the sub-genus Eulima Risso. The rest of the 

 species, all fluviatile, form the sub-genera Melania, and Melanopsis 

 FERUSS., LAM. 



Sp. Melania amarula LAM., Helix amarula L., EUMPH. Amb. RariteitJc. Tab. 

 33, fig. F, F; BLAINV. Malacol. PL 35, fig. 7; Melania Rangii DESH., 

 Melan. tuberculosa BANG, GUERIN Mag. de Zool. 1832, Moll. PI. 13 (a fig. 

 with the animal) &c. The species are especially numerous in the rivers and 

 fresh waters of the Sunda Islands ; comp. MOUSSON Molluslcen von Java, 

 1849, s - *>5 79. An European species, Melan. helvetica MICHELIN, GUKR. 

 Mag. de Zool. 1831, Moll. PI. 37, forms the typus of the gen. Pyrgula DE 

 CHRISTOF. and JAN. ; DESHAYES thinks this species ought not to be sepa- 

 rated from Melania; others refer it to Paludina. 



(Melanopsis. Columella truncated, disjoined from labrum by a 

 sinus.) 





