PALUDINA. 25 



FAMILY II.— PALUDINIDiE. 



Body oval, elongated, spiral, capable of being entirely con- 

 tained within its shell, provided with a prominent snout ; eyes 

 placed either on a short stalk at the base of the tentacles, or 

 sessile ; foot oval, much dilated ; gill placed within the mantle ; 

 sexes separate ; lingual ribbon usually with a few rows, each 

 having seven teeth, one inedia?i or central tooth, and three on 

 each side of it. 



Shell dextral, conical, ventricose ; spire long, symmetrical ; 

 mouth oval ; operculum oval, either horny or testaceous, irregu- 

 larly concentric. 



The members of this family are vegetable feeders ; 

 some of them are oviparous, and others ovoviviparous ; 

 in the latter case the fry, to the number of from twenty 

 to thirty, remain in the ovary of the parent for about 

 two months, their opercula being formed before they 

 are born, and they are excluded three or four at a 

 time at intervals of several days. 



GENUS I.—PALUDI'NA* LAMARCK. 



Animal ovoviviparous; ^(?j- placed on short footstalks ; oper- 

 culum horny, irregularly concentric ; nucleus placed towards 

 the inner side. 



When the fry of the PahidincB are excluded the 

 epidermis of the last formed whorl is furnished with 

 three rows of recurved bristles, which are shed after 

 a time, and replaced by the brown bands with which 

 the full-grown shell is marked. 



I. PALUDINA CONTEC'TA,t MiLLET. Pl. IV. AND IX. 



Body black, dark-grey, or brownish, spotted with yellow ; head 

 small, very globular ; snout large, bilobed ; tentacles blackish 

 with yellowish tips, long, thick at their base, diverging consider- 



* Living in marshes. f Covered (by the operculum). 



