On the Animals and Teeth of some Gasteropodous Mollusca. 97 



longitudinal rows, 1 • 1 • 1 , central far apart from each other, and the 

 lateral teeth, lunate, with a slightly denticulated, nearly straight, 

 front edge, and a rather strong concave tooth at each end ; lateral 

 teeth versatile, large, with a nearly equal hasal and apical, conical, 

 curved process. Male organ slender, elongate, tapering, yellow, 

 compressed. Operculum ovate, acute, thick, horny, annular, nucleus 

 apical. 



Triumphis distorta. Panama. 



Lingual membrane elongate ; teeth in three longitudinal series, 

 1 ■ 1 • 1 ; central teeth very small, far apart ; lateral large, versatile, 

 with two basal unequal, and one larger terminal curved process. 

 Operculum ovate, acute, very thick. 



Cyclope (Nassa) neritinea. 



Nucleus prominent above the surface of the apex of the semi-adult 

 shell, turrited, spiral, dextral, of three or four transversely sulcated 

 flat whorls, with a blunt tip, at length deciduous, leaving a flat, spiral, 

 rather callous scar. The whorls of the shell of the hatched animal 

 suddenly enlarged, thick ; smooth, spotted, forming a sudden contrast 

 to the whorls of the nucleus. 



Risso formed a genus, name Nanina, from the young state of the 

 shell. 



Fam. BucciNiD^. 



CUMA SULCATA. 



Operculum horny, ovate, triangular, with a deep notch on the 

 middle of the broad side, with a broad callous margin on the inner 

 angular edge of the inner surface. Body and foot with a deep groove 

 on the inner side, formed by the fold on the inner lip of the shell, 

 like the notch in the operculum ; foot folded up behind and together 

 in front, forming a j^-shaped groove, with a cross groove in front ; 

 tentacles close together at the base, diverging, short, compressed, 

 sharp-edged, eyes on the outer side near the tips, which are more 

 slender and acute above them; proboscis moderately elongate, cylindri- 

 cal, subclavate, completely retractile ; lingual membrane very narrow 

 and elongate, horny ; teeth dark-coloured when adult, in three longi- 

 tudinal series, 1 • 1 • 1 ; the central teeth broad, transverse, about 

 half the width of the lingual membrane, with seven distant conical 

 denticulations on the front edge, the central denticle forming a con- 

 tinued central ridge, the lateral denticulations unequal, the central 

 of the three larger, the outer one on the outer margin of the tooth ; 

 the lateral teeth small, conical, curved, acute, versatile with a simple 

 rather elongate base. 



B. Odontoglossa. 

 Fam. Fasciolariad^. 



Fasciolaria salmo. 



Operculum ovate, acute, smooth, slightly concentrically wrinkled ; 

 apex of this individual reproduced and rather rounded. Animal bright 

 Ann. ^ Mag. N. Hist. Ser.2. Fb/.xix. 7 



