HELIX. 913 



lucid, smooth and glossy, of a horn-colour, and has five 

 whirls, with the spire nearly flat ; the base is more opake, and 

 of a lighter colour, and has a large deep umbilicus. H, ni- 

 tida of Gmelin is Nautilus lacustris. 



TENUIS. 60. Shell umbilicated, pellucid, and glos- 

 sy, with six transversely striated whirls ; 

 aperture semi-lunar. 



Helix tenuis. Gmelin, p. 3641. 

 Helix lucida, Var. Montagu Test. p. 426. 

 Helix, No. 326. Schroeter Einl. ii. p. 270. 

 Cochlea terrestriformis, &c. Schroeter Fluss. p. 258. t. 5. 

 f. 32. 



Variety/. Shell smaller, with only four whirls. 

 Helix pellucida. Pennant Zool. iv. p. 138. 

 Helix, No. 220. Schroeter Einl. ii. p. 239- 

 Cochlea umbilicata quatuor spirarum teretium. Schroeter 



Fluss. p. 259. t. 5. f. 33. 

 Martini Berl. Mag. iv. t. 7. f. l6. 



Inhabits a water-course near Penzance ; and the Variety in wet 

 drains and ditches about Newbury. Montagu. 



Shell four or five lines in diameter, pellucid, and of a horn- 

 colour ; there can be no doubt that the Variety which Mon- 

 tagu has described of his H. lucida is the //. tenuis of Gme- 

 lin, and the following is Mr. Montagu's observation : " We 

 have found a shell inhabiting wet places, and once alive 

 under water, so much like this, that we dare not give it a 

 distinct place, though we are much inclined to believe it a 

 different species. It is more pellucid, the apex more pro- 

 duced, and never has that opake greenish-colour at the base : 

 that found under water (which we take to be Schroeter's 

 figure 32.) was of a light transparent horn-colour. Others 

 taken in wet drains and ditches, about Newbury in Berk- 

 shire, are of a rufous horn-colour (which is probably Schroe- 

 ter's fig. 33) : the animal is black, and when alive gives the 

 shell a deep chocolate brown colour. This last we have 

 also found on a swamp, in a wood belonging to Lord Clif- 

 ford in Devonshire, rather lighter in colour." 



CELLARIA. 61. Shell umbilicated, pellucid, glossy, 

 with five depressed yellowish whirls, and the 

 base white ; aperture large. 



Helix cellaria. Muller Verm. ii. p. 28. Chemnitz, ix. 



