178 BRITISH MOLLUSKS. 



C. elegans is not found in Scotland, nor in Northern Europe. It 

 is most abundant, along with C. sulcatum, in the centre and south 

 of Europe, and in the islands of the Mediterranean ; and it has 

 been collected in the Canary Islands. 



Acme lmeata. (Considerably enlarged.) 



Genus II. ACME, Hartmann. 



Animal ; rather elongated, carrying a slender transparent cylin- 

 drically turriculate shell, head proboscis-like, tumid and then 

 attenuated, transversely wrinkled, tentacles bristle-like, not 

 swollen at the tip, eyes at the base of the tentacles inclining 

 outwardly, foot bearing a horny subspiral operculum. 

 Shell ; cylindrically elongated, fuscous horny, transparent, glossy, 

 of sis rather slender closely lineated whorls, aperture small, 

 more or less sinuated at the upper part. 

 Acme is a minute form, carrying a transparent amber shell, which, 

 though elongately turreted, is barely the twelfth of an inch in length. 

 Its affinity with the preceding genus is shown by the proboscidiform 

 head, and slender tentacles with the eyes at the base inclining out- 

 wardly, and by the presence of an operculum, which in this instance 

 is horny and subspiral. 



Acme lineata is diffused pretty generally throughout Europe, and 

 the genus is not found elsewhere. M. Moquin-Tandon not only 

 makes three species of the Acme lineata, but he characterizes those 

 in which a marginal cleft in the aperture of the shell is more ap- 

 parent than in others, as subgenera, Auricella and Platvla. He 

 has studied the living animal with care, and describes its habits 

 with much interesting detail. 



Our British species of Acme is : — 



1. lineata. Shell of six transparent flatly convex whorls, more 

 or less linearlv striated. 



