140 DACTYLINJS. 



Ex. H. minor, Martini, pi. 15, fig. 1. Shell, H. veu- 

 tricosa, Lamarck, fig. 1, a. 



The animals are variegated with beautiful colours, and 

 crawl with vivacity ; they have the singular power of 

 spontaneously detaching a portion of the foot when mo- 

 lested, resembling, in this respect, HaUotidea and Gena. 

 They are found in Ceylon, Mauritius, the Feejee Islands, 

 and in Mexico. At Mauritius they are caught with lines 

 baited with small pieces of flesh. 



Species of Harpa. 



cancellata, Chem. minor, Mart. 



costata, Linn. nablium, Mart. 



crassa, Phil. uobilis, Mart. 



crenata, Swains. rosacea, Mart. 



gracilis, Brod. striatula, A. Adams. 



major. Mart. ventricosa, Lam. 



Sub-fam. DACTYLTN.^. 



Head and tentacles more or less concealed. Mantle 

 with a tapering lobe in front, and an appendage behind 

 which covers the spire, or reposes in the channelled 

 suture. 



Operculum wanting, or elongated and thin, with an 

 apical, subspiral nucleus. 



Shell solid, smooth ; inner lip more or less plicate ante- 

 riorly. 



Genus OLIVANCILLARIA, D'Orbigny. 



Head and tentacles concealed. Mantle with a large, 

 thick, fleshy appendage behind. Foot very voluminous, 



