OBELISCUS. 229 



The PyramidellcB live in sandy bays and on shallow 

 mud -banks, concealing themselves under the surface, and 

 indicating their presence by the formation of slender, 

 raised tracks; they are found in the Eastern Archipelago, 

 New Holland, and the Mauritius. 



Species of Pijramidelht. 



acicula, A. Adams. metula, A. Adams. 



aclis, A. Adams. minuta, Phil. 



ambigua, Phil. mitralis, A. Adams. 



auris-cati, Chem. nitida, A. Adams. 



corrugata, Lam. nodicincta, A. Adams. 



glans, Fieeve. propinqua, A. Adavis. 



gracilis, A. Adams. subulata, A^. Adams. 



niagnifica, Adams and Reeve. variegata, A. Adams. 



Genus OBELTSCUS, Humphrey. 



Shell subulate, turreted, many-whorled, smooth; spire 

 pointed, nucleus sinistral; aperture serai-oval, entire, 

 rounded anteriorly; columella straight, plicated; outer 

 lip acute. 



Ea:. O. punctatus, Chemnitz, pi. 24, fig. 5. Oper- 

 culum, O. dolabratus, Linmeus, fig. 5, a. Shell, O. dola- 

 bratus, fig. 5, b. 



This genus differs from Eullmella in the plicated 

 pillar, from Pi/ramidella in not being longitudinally 

 ribbed, and from the other members of the family in its 

 tapering, subulate form, and the plaits on the columella. 

 Many extinct species, referred to certain genera, may 

 possibly be found to belong to this type, which appears 

 to have been well represented, and to have comprised 



