138 MANUAL OF THE MOLLUSCA. 



I 



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, Megerlc. i 



Ti/pe, L. fuscus. PI. IX., fig. 22. | 



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

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

 epidermis olivaceous; operculum pauci-spu'al. ^| 



Distr., sp. Europe, Oregon. , 



FAMILY VII. Paludtnid^. i 



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

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

 concentric. i 



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



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



world. 



Paludina, Lam. River-snail. 



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

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



Shell turbinated, with romid 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 paludinse are vi%aparous ; the shells of j 

 the young are ornamented with spiral rows of epidermal cii-ri. i 



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 sm-face i 



as she proceeds ; the young are hatched in three or fom* weeks, and attain j 



their full growth in the second year (Bouchard). ' 



Ampullaria, Lam. Apple-snail, or idol-shell. j 



Etym., ampulla, a globular flask. I 



Ex., A. globosa, PI. IX., fig. 30. Syn., pachylabra, Sw. j 



Shell globular, with a small spire, and a large ventricose body- whirl ; 1 



peristome thickened and slightly reflected. Operc. shelly. | 



