230 



PYRAMIDELLIDiE. 



species of larger dimensions in past epochs than in the 

 present time ; examples occur even in the oldest fossili- 

 ferous strata. 



Species of Obeliscus. 



aciculatus, A. Adams. 

 acutus, A. Adams. 

 annulatus, A. Adams. 

 attenuatus, A. Adams. 

 balteatus, A. Adams. 

 bruiineus, A. Adams. 

 cinctus, Reeve. 

 clavulus, A. Adams. 

 conicus, G. B. Adams. 

 dolabratus, Linn. 

 elegans, A. Adams. 

 fastigium, A. Adams. 

 gracilis, Brocc. 

 hastatus, A. Adams. 

 metula, A. Adams. 

 monilis, A. Adams. 



perforatus, A. Adams. 

 pulchellus, A. Adams. 

 punctatus, Chem. 

 pusillus, A. Adams. 

 scitulus, A. Adams. 

 spiculum, A. Adams. 

 striatulus, A. Adams. 

 stylinus, A. Adams. 

 eulcatus, A. Adams. 

 terebelloides, A. Adams. 

 terebellum, Mi'dl. 

 teres, A. Adams. 

 tessellatus, A. Adams. 

 turritus, A. Adams. 

 ventricosus, Guerin. 



Genus TURBONILLA, Risso. 



Operculigerous lobe with a minute, conical appendage 

 on each side. 



Shell slender, elongated, many -whorled, longitudinally 

 ribbed ; apex of spire with a persistent, embryonic, sinis- 

 tral nucleus ; aperture oblong or subquadrate, peristome 

 incomplete; columella straight, simple, edentulate, and 

 without a plait. 



Syn. Chemnitzia, D'Orh. Pyrgiscus, Phil. Ortho- 

 steles, Arad. and Mag. 



