PLEUROTOMA. 375 



Channel Isles; I obtained it alive by dredging oif St. Ca- 

 therine's Bay, Jersey, in 10-12 f., and dead at Guernsey, 

 in 18 f. Fossil (var. Philberti) ? Ireland (Smith); Coral- 

 line Crag (Wood) ; Touraine, south of France, and Italy 

 (Homes and others) . The range of this species and the 

 variety Philberti, as recent, comprises Christiansund, 

 30-50 f. (Danielssen), Bergen (Sars), Bohuslan, 18-50 f. 

 (Malm) J north Atlantic, from Normandy to Madeira and 

 the Canaries, Mediterranean, Adriatic, and ^gean; 

 shore to 55 f. 



The animal is sluggish. Very young shells of the 

 typical form are extremely slender and finely pointed. 



There are several obsolete or useless synonyms. Man- 

 gelia purpurea of Bisso can scarcely be this species ; he 

 described it as subfossil only. 



Genus II. PLEURO'TOMA*, Lamarck. PL VII. f. 2. 



Shell forming a more or less lengthened cone : spire tur- 

 reted ; apex regular and blunt : mouth narrow : outer lip 

 notched at the side, below its junction with the periphery ; 

 inside smooth : operculum possessed by some species, and re- 

 sembling in shape an elongated pear, with the nucleus or point 

 at the base. 



Although the notch in the outer lip of British species 

 is usually slight, such is not the case in P. nivalis, which 

 has as deep a slit as many typical species of Plearotoma ; 

 the depth of the notch or slit is merely a comparative 

 character. 



This genus has been very unscientifically and need- 

 lessly divided by authors, and has received various 

 names. Mangelia (correctly Mangilia, from Mangili, 

 an Italian naturalist) is one of these synonyms, and has 

 been attributed to Bisso on Leach's authority; but Bisso 



* From a notch in the side of the lip. 



