74 BRITISH MOLLUSKS. 



12. Helix lapicida. Stone-cutter Helix. 



Shell; openly deeply unibilicated, lenticularly depressed, fawn 

 brown, variegated, spire obtusely convex, 

 whorls five, slopingly convex, sharply keeled 

 at the periphery, minutely granosely sha- 

 greened throughout, last whorl suddenly de- 

 flected at the aperture, constricted behind the 

 lip; aperture horizontal, transversely oval, lip , 



continuous, expandedly reflected, white. 



Helix lapicida, Linnaeus (1758), Syst. Nat. 10th edit. p. v i ,; ^ 



768. ^-t^^" 



Helix acuta, Da Costa (1778), Test. Brit. p. 55. pi. iv. f. 9. 



Helix affinis, Gmelin (1788), Syst. Nat. p. 3621. 



Vortex lapicida, Oken (1815), Lefirb. Nat. vol. iii. p. 314. 



Carocolla lapicida, Lamarck (1822), Anim. sans vert. vol. vi. part 2. 



p. 99. 

 Helicigona lapicida, Eisso (1826), Hist. Nat. Europ. Mend. vol. iv. p. 66. 

 Chilotrema lapicida, Leach (1831), Turt. Man. p. 106. 

 Latomus lapicida, Fitzinger (1833), Syst. Verz. p. 97. 

 Lenticula lapicida, Held (1837), Isis, p. 913. 

 Helix (Vortex) lapicida, Moquin-Tandon (1855), Hist. Moll. vol. ii. p. 137. 



pi. xi. f. 22 to 27. 

 Hab. Northern and Central Europe. Central and Southern England. (In 



limestone and chalky districts, chiefly among rocks.) 



In this species we have another isolated type, Carocolla of Schu- 

 macher and Lamarck, in which the shell is compressed into the 

 shape of a lens, with the whorls attenuated and keeled at the peri- 

 phery. There are not many of the type in Europe ; it is an inter- 

 tropical form, and has its maximum development in the H. Listeri 

 and jparmnla of the Philippine Islands. H. lapicida has rather a 

 curious range of geographical distribution. It is not found south of 

 the Pyrenees, but extends northward from that latitude as far as 

 Sweden ; yet it is not found in Scotland and the northern counties 

 of England, nor has it been collected in Wales or Ireland. From 

 Yorkshire and Lincolnshire to Portland Island and North Devon, 

 H. lapicida appears in occasional plenty. The animal is a pallid 

 rufous brown, grey towards the posterior end, covered throughout 

 with promiscuous dark tubercles. The shell has a shagreen sur- 

 face of fine grains. The last whorl being suddenly deflected, the 

 aperture is very obliquely horizontal, and the margin is white, con- 

 spicuously expandedly reflected. This colourless expansion of the 



