60 MOLLUSCA. 



There is one species wliich is remarkable for a border and stony 

 traverse, on tlie internal face of its operculum *. 



The organs of respiration in these animals are arranged as in the 

 Cyclostoma?, and like tlic latter they can live out of water f . 



Melaxia, Lam. 



A thicker sliell ; the aperture, higher than it is wide, enlarges oppo- 

 site to the spire ; the columella Avithout plicpe or umbilicus ; length of 

 the spire very various. 



The Melaniae inhabit rivers, but are not found in France, the ani- 

 mal has long tentacula, the eyes being on their external side, and at 

 about the third of their length +. The 



RissoA, Freminv. — Acmea, Harim. 



Differs from Mclania, because the two edges of the aperture unite 

 above§. The 



Melaxopsis, Feriins., 



Where the form is nearly that of a Melania, differs from it in a 

 callus on the cohmiella, and in a vestige of an emargination near the 

 bottom of the aperture, which seems to indicate a relation with the 

 Terebra? of Brugieresl]. In the 



PiRENA, Lam., 



We not only find this little sinus below, but likewise a second on 

 the opposite side^. 



These two subgenera, as well as the Melanise, inhabit the rivers of 

 southern Europe and of all hot countries. 



There are two genera, detached from the Volutae, which, but that 



* The Hel. nerileUa, List., LXI, 59, copied Blainv., Malac, xxxix, 2. 



t It is from this circumstance that M. de Fi'-russac has been induced to class 

 this subgenus with that of the Cyclostomee in an order which he names the Pul- 

 monea OpercvMa. See the Monograph of this genus by M. Gray, Zool. Journ., 

 Nos. 1 and 2. 



X Mchuiie thiure CMclaniii (imaruht,hAm.), Chciun., Tab., KU, f. 1218 and 1219; 

 from the Isle of France and Madagascar. 



Add, Mel. tninralu, Lam., Encyclop., pi. 458, f. :;, a — b ; — Mel. courcltiUi, Id., 

 Encych>p., pi. 45S, f. 5, a — b., and a great many fossil species, among which are, 

 Mel. seini-placuta, Defr. ; — Mel. Cui-ieri, Desh., Coq. Foss., des environs de Pans, 

 tome II, pi. xii, f. 1, 2; — Md. constelhtta, Lam. 



§ M. de Freminville describes seven species in the Xouv. Bullet, des f^c. 

 Nat. de la Soc. Phil., 1814, p. 7, and M. Audouin, three, in the Descr. de I'Eg. ; 

 Riss. Franiiuillii, Coq., pi. iii, f. 20 ; — Riss. DesmuiL!<tii, lb., 21 ; — Riss. Orbiynii, 

 lb., f. 22. 



II Melan. burcinoulea, Feruss., Mem. de la Soc. d'Hist. Nat. de Paris, tome 1, pi, 

 \ii, f. 1 — 11, &c. See Sowerhy, No. XXII. 



^ Pir. terebrans, Lam.; List. Tab. 115, f. 10; — Pir. mwhiyascaricnsis, Encycl., 

 pi. 4 58, f. 2, a, b, &.C. 



