spire-shells and Marsh-snails 231 



pale brown, glossy, and semi - transparent. The 

 animal is much like the Round - mouth, but its 

 tentacles have not the enlarged tips of that species, 

 the operculum is horny instead of stony, and fits 

 into an oval mouth. It is an active little creature, 

 and niay be detected by sharp eyes as it ranges over 

 the moss, dead leaves, and decaying trees in damp 

 woods or dry ditches. 



The Spire-shells (Rissoa) form one of the most 

 largely represented genera of British shells, something 

 like a quarter of a hundred native species being in- 

 cluded in it. Like Acvie they have an elongated 

 shell, but here the shape is distinctly conical, the last 

 or body-whorl constituting one- 

 half to two-thirds of the whole. 

 The mouth of the shell is more or 

 less round, fitted with a horny , . , 



' . -^ Latticed Thick-lipped 



operculum ; there is rarely an spire-sheii spire-sheii 

 umbilicus. The animals are very ^^7" (R. mcmhran 



^ cancellata) cicea) 



like Winkles ; the body is slender, 

 the head produced into a bilobed snout, and the 

 mouth armed with a pair of jaws and a short radula. 

 The blunt-tipped tentacles are more or less hairy, and 

 bear the eyes on small prominences near their base. 

 The foot is divided down the middle as in the Winkles, 

 but only half-way. From the hinder extremity of 

 the lobe to which the operculum is attached, an 

 appendage like a tentacle is given off from each side, 

 thus showing a relationship with the Chink-shells 

 (Lacuna). The shells are all very small, but their 

 forms are beautiful. The Spire-shells may be found 

 on seaweeds and Zostera at all depths between high 

 water and 100 fathoms, according to species. The 



