DACTYLID.E. 139 



Fam. DACTYLID.E. 



Teeth on lingual membrane in three series (Tri), tlie 

 central broad, the lateral versatile. Mantle enclosed, the 

 siphon recurved. Foot voluminous, usually reflexed over 

 the sides of the shell, and fissured on each side in front. 



Operculum small, often wanting or rudimentary. 



Shell porcellanous, usually polished, last whorl often 

 enrolled round the others ; aperture ending anteriorly 

 in an oblique fissure. 



The operculum is absent in Harpa and Dacfi/lus, and 

 also in some of the ventricose species of Ancillce with 

 wide apertures ; but in Olivella, and in many of the smaller 

 Ancillce, it is always present, though of moderate size. 



Sub-fam. HARPIN.^. 



Head and tentacles exposed ; eyes conspicuous, deve- 

 loped. Mantle simple, enclosed, without a tapering ap- 

 pendage in front. Foot large, flat, not reflexed on the 

 sides of the shell. 



Operculum none. 



Shell ventricose, whorls ribbed ; inner lip simple ante- 

 riorly. 



Geniis HAKPA, Rumphius. 



Shell oval, ventricose ; spire short, apex acute, whorls 

 longitudinally ribbed, ribs ending posteriorly in sharp 

 points ; aperture oblong, large, emarginate anteriorly ; 

 outer lip thickened, forming the last rib. 



Syn. Cithara, Klein. Harparia, Rajin. Harpalis, 

 Link. Lyra, Griff., not Linn. 



