168 THE ANIMAL KINGDOM. 



HELIX RTJFESCENS. 



Helix rnfescens, a reddish-brown snail, flattish, and in 

 the middle of the largest whorl it has a narrow white line 

 or band, which distinguishes it. 



HELIX VIRGATA. 



These pretty small brown and white banded snails are 

 most abundant on our sandy sea-coasts, quite covering the 

 marine plants there ; also they are often in great numbers 

 on sandy commons on the wayside turf. 



The palates of all these terrestrial gasteropods are upon 

 the same plan broad, short, and with long rows of teeth ; 

 the prettiest variety is found in the palate of 



ZONITES, OR HELIX NITIDA. 



This small snail is a species passing out of the genus 

 Helicidse ; it is small, transparent, pale-yellow, or light- 

 brown, with five whorls, and the under side clouded with 

 white ; found under stones, and in violet beds at the roots 

 of the plants, also in cellars and yards in cities. The side 

 teeth slope towards the centre, which is occupied by what 

 may be called double teeth, or teeth with several projections. 

 There are few prettier palates than this of the common little 

 Zonites, or Cellar-snail. 



PALATE OF WHELK. 

 (Succinum undatum.) 



Compare this with the palate of any of the terrestrial 

 gasteropods snails or slugs and the difference of struc- 

 ture will be apparent : instead of that broad short mem- 

 brane thickly set with rows of nearly uniform teeth, we have 

 here a ribbon-like tongue, having strong serrated teeth at 

 the edges, and rows of small finer ones between them, better 

 observed by polarized light, which makes it a splendid 

 object. This tongue is contained in a long fleshy proboscis, 

 with which the Whelk bores through the shell of those 

 molluscs which serve it for food, and the muscles by which 

 it moves this tongue are immensely strong, not only drawing 



