DACTYLUS. 143 



Shell oblong, subcylindrical, polished ; spive short, su- 

 ture canaliculated ; aperture long, narrow, notched in 

 front ; columella obliquely plicate, sulcated, or striated, 

 with a callosity at the hind part ; outer lip simple, rather 

 thick. 



Syn. Oliva, Briig. Ancillaria, Risso, not Lam. Oli- 

 varia, Rafin. Olivarius, Diim. 



Ex. D. Mauritianus, Martini, pi. 15, fig. 4. Shell, D. 

 Mauritianus, fig. 4, a. 



The species of Daclylus, commonly known under the 

 name of " Olives," are chiefly tropical in their geogra- 

 phical distribution. They live on sandy flats, and may 

 be found by following the traces they leave by burrowing 

 under the surface as the tide retires ; they are very active, 

 and glide with considerable quickness. In the genus, as 

 restricted, the callus of the inner lip is produced pos- 

 teriorly beyond the spire, and there is a prominent cal- 

 losity on the anterior part of the last whorl. 



Species of Dactybis. 



avellana, Lam. inflatus, Lam. 



bulbiformis, Duclos. tuberosus, Bolt. 



bulbosus, Bolt. undatus, Lam. 



Sub-gen. strephona, Browne. 



Shell subcylindrical, polished ; spire short, pointed, suture 

 channelled as far as the apex ; last whorl simple ; columella 

 obliquely plicate. 



coniformis, Phil. incrassatus, Soland. 



Cumingii, Reeve. ispidus, Li?ik. 



harpularius, Lam. jaspideus, Duclos. 



