o NA88IDJE. 



Subgenus ADINUS, H. and A. Adams. Shell subulate, spirally striated ; 

 columella abmptly truncated afc base ; inner lip corrugated, with a 

 callosity at hind part ; outer lip grooved internally, externally margin- 

 ated. 



NASSA, Lam. Shell ovate, ventricose, body whorl variously sculptured ; 

 aperture ovate, with a short, reflected, truncated, anterior canal ; 

 inner lip smooth, often widely spread over with enamel, with a posterior 

 callosity or blunt dentiform plait ; outer lip dentated, internally 

 crenulated. Margin of operculum serrated or entire. Dentition, PI. 3, 

 figs. 22 to 25.* 



The following "snbgenera." may be, retained as convenient 

 group designations, although the species, varying much in their 

 sculpture cannot always be positively assigned. 



Subgenus ARCULARIA, Link. Body whorl gibbous on the back; spire 

 produced ; callus of inner lip greatly extended and covering the spire. 



Subgenus NAYTIA, H. and A. Adams. Shell smooth ; aperture -with a 

 channel at the hind part continued up the spire. 



Snbgenus ALECTRION, Montf. Spire elevated, whorls glabrous, polished 

 or papillary ; inner lip spreading ; outer lip denticulate, not variced 

 externally, 



Subgenus ZEUXIS, II. and A. Adams. Spire elevated, smooth, or longi- 

 tudinally plicate, polished ; inner lip with the callus defined, or some- 

 what spreading ; outer lip externally variced, sometimes dentate 

 anteriorly.f 



Subgenus ACICTTLINA, H. and A.Adams. Shell turrited, polished, smooth 

 or longitudinally plicate : inner lip with the callus sharp, straight, 

 defined ; outer lip produced in the middle, variced externally. 

 ^/Subgenus PHRONTIS, H. and A. Adams. Spire elevated, acuminate, 

 whorls ribbed or nodulose, distinctly shouldered ; inner lip smooth, with 

 an extended, thickened callus, outer lip with an external varix. 



:: ' Messrs. IT. and A. Adams in their "Genera of Recent Mollusca," 

 have made a Genus Amycla in Columbeflidae, and included in it some 

 species which are decidedly Nassids ; the dentition of one of these errone- 

 ously placed species, N. (Bucc.) cornicula, Olivi (PI. 3, fig. 24), has been 

 figured by Troschel as a type of that of the genus Amycla, which he has 

 accordingly removed to Nassidse. 



f NASSODONTA, H. Adams. Shell oval ; spire short, last whorl sulcate 

 anteriorly ; aperture sinuated in front, canaliculate behind ; columella 

 callous, plicate anteriorly ; lip acute, thickened and dentate within, with 

 an anterior marginal denticulation. Operculum and animal unknown. I 

 have included the single species in Zeuxis. 



