138 MANUAL OF THE MOLLUSCA. 



the space between their lips and foot, like the geometric caterpillars (Gray). 

 They are found semi-fossil, along with the human skeletons in the modern 

 limestone of Guadaloupe. 



Distr., 15 sp. W. Indies, Brit., Medit., Rio, Cape, Mauritius, Philippines, 

 Australia, Pacific (Cuming). 



? LITHOGLYPHUS, Megerle. 



Type, L. fuscus. PI. IX., fig. 22. 



Shell naticoid, often eroded ; whirls few, smooth ; aperture large, entire ; 

 peristome continuous, outer lip sharp, inner lip callous ; umbilicus rimate ; 

 epidermis olivaceous ; operculum pauci-spiral. 



Distr. t sp. Europe, Oregon. 



FAMILY VII. PALUDTNID^E. 



Shell conical or globular, with a thick, olive-green epidermis ; aperture 

 rounded ; peristome continuous, entire ; operculum horny or shelly, normally 

 concentric. 



Animal with a broad muzzle ; tentacles long and slender ; eyes on short 

 pedicels, outside the tentacles. Inhabiting fresh-waters in all parts of the 

 world. 



PALUDINA, Lam. River-snail. 



Etym., palm (paludis) a marsh. Syn., viviparus, Gray. 



Type, P. Listen. PL IX., fig. 26. (P. vivipara, fig. 61.) 



Shell turbinated, with round whirls ; aperture slightly angular behind ; 

 peristome continuous, entire ; operc. horny, concentric. Animal with a long 

 muzzle, and very short eye-pedicels; neck with a small lappet on the left side, 

 and a larger on the right, folded to form a respiratory siphon ; gill comb-like, 

 single ; tongue short ; teeth single, oval, slightly hooked and denticulated ; 

 uncini 3, oblong, denticulated. The paludinee are viviparous ; the shells of 

 the young are ornamented with spiral rows of epidermal cirri. 



Distr., 60 sp. Rivers and lakes throughout the N. hemisphere ; Black 

 sea, Caspian. 



Fossil, 50 sp. Weald. Brit., &c. 



Sub-genus. Bithinia (Prideaux), Gray. B. tentaculata, PI. IX., fig. 27. 

 Shell small ; operc. shelly. Animal oviparous ; with only one neck-lappet, 

 on the right side. The bithinise oviposit on stones and aquatic plants ; the 

 female lays from 30 to 70 eggs in a band of three rows, cleaning the surface 

 as she proceeds ; the young are hatched in three or four weeks, and attain 

 their full growth in the second year (Bouchard). 



AMPULLAIIIA, Lam. Apple-snail, or idol-shell. 



Etym., ampulla, a globular flask. 



jEr.. A. globosa, PI. IX., fig. 30. Syn., pachylabra, Sw. 



Shell globular, with a small spire, and a large ventricose body-v 

 peristome thickened and slightly reflected. Operc. shelly. 



UU.U. autaiii 



Ddy-whirl ; 



