DEFRANCIA. 361 



consisting of spines, which are arranged in a single row on 

 each side and terminate in sharp points. Sexes distinct. 



SHELL spindle-shaped, or forming a lengthened cone with 

 a pointed base : spire tapering or turreted : mouth oblong : 

 outer Up fissured or notched : canal nearly straight : pillar 

 smooth: operculum (when present) like that of Trophon or 

 Fusus. 



This family ought to be separated from the Conidce, 

 with at least as much justice as Muricidae and Nassida 

 have been removed from the Buccinida. According to 

 Loven the proboscis in Conus is not retractile. Wood- 

 ward enumerated 430 recent and 378 fossil species of 

 Pleurotoma ; the geographical and bathymetrical distri- 

 bution of the former is very extensive. 



Genus I. DEFRAN'CIA*, Millet. PL VII. f. 1. 



SHELL spindle-shaped : spire tapering ; apex somewhat 

 stiliform (as in Cerithiopsis), finely pointed, and minutely re- 

 ticulated : mouth open : outer lip fissured at its junction with 

 the periphery ; inside grooved : operculum none. 



M. Millet constructed the present genus from some 

 shells of the " calcaire grossier/* which have the outer 

 lip " sinue a sa partie superieure," in contradistinction 

 to Pleurotoma, in which the outer lip is notched at the 

 side. The apex of the spire is also very different. There 

 is, besides, a certain diversity of form and sculpture 

 in each of these groups of species, although they are 



" all affin'd and kin." 



Defrancia was used by Bronn for a genus of Polyzoa ; 

 but that is a synonym of Pelagia, Lamouroux. 



* Named in honour of M. Defrance, a well-known French naturalist 

 and geologist. 



VOL. IV. B, 



