AMPULLARTIDiE. 275 



widel}^ sinuated in the middle. P. Tanganyicensc^ Smith 

 (Ixxiv, 10). Lake Tanganyika, Africa. 



TANGANYiciA, Crosse. Shell globose, ampullariform, rimate, 

 covered by a yQxy thin epidermis ; columellar lip lobed below. 

 Operculum at first spiral, afterwards concentric. P. riifojilosa, 

 B. A. Smith (Ixxiv, 11). Lake Tanganjdka. 



MEKONGIA, Crosse and Fischer. Aperture contracted, appear- 

 ing like a gigantic Stenothyra. Cambodia. P. JuUieni, Desh. 

 (Ixxiv, 12). 



Larina, a. Ad. 



Syn. — Robinsonia, H. Nevill. 



Shell imperforate, semigiobose, thin ; spire obtuse, whorls few, 

 tumid, covered with an olivaceous epidermis, last whorl lai'ge 

 and ventricose ; aperture wide, ovate ; outer lip simple, regular, 

 acute. Operculum annular, horny, ovate. Moreton Bay, Australia ; 

 possibly from a stream in the vicinit3^ 



Adams thinks it is related to Paludina, but it may be a marine 

 shell, and I have included it in the Naticidse of this work (p. 

 206). Several Indian species, apparently of the same genus, 

 have been described under the generic name of Robinsonia. P. 

 Ceylonica, Wevill (Ixiii, 51). 



Cleopatra, Troschel. 



Distr. — Several species. Egypt and E. Africa. G. hulim- 

 oides, Oliv. (Ixxiv, 13 '. 



Shell turbinate, with moderate spire. Operculum subspiral. 

 The spire is more elevated than in Paludina, and the operculum 

 differs. 



Lioplax, Troschel. 



Syn. — Haldemania, Try on. 



Distr. — A few United States species. L. subcarinata, Say 

 (Ixxiv, 14). 



Shell with elevated spire, very convex, somewhat carinated or 

 angulated whorls, and deep sutures. Operculum concentric, but 

 with a spiral nucleus. 



LioPLACODES, Meek. Differs from Lioplax in its more elon- 

 gated form, smaller body-whorl, more constricted suture, aper- 

 ture angular posteriorly ; peritreme continuous ; umbilicate. 

 L. veterna, Meek and Hayden. Jurassic ; U. S. 



Family AMPULLARIID^. 



Shell globular, with large body-whorl, and more or less 

 depressed spire ; sometimes planorboid. Aperture slightly ex- 

 panded. Operculum concentric. 



Animal with a long siphon, formed by the left neck-lappet ; 

 left gill developed, but much smaller than the right; muzzle 



