HELICINA, 



GENERIC CHARACTER. 



Shell subglobular; spire depressed or but little elevate4; 

 aperture semiorbicular, modified by the preceding volution; 

 base with a more or less obvious callosity covering the 

 umbilicus; labrum acute or a little reflected ; columella 

 at base a little prominent and joined to the labrum at an 

 angle ; operculum horny, and with concentric elements. 



Animal terrestrial, globular, subspiral; head rostrated; 

 rostrum bilabiated at the tip and shorter than the tenta- 

 cula, which are two in number, filiform, and have the 

 prominent eyes at the exterior part of their base, upon a 

 tubercle ; the organs of respiration as in Cyclostoma ; the 

 branchial cavity communicates with the atmosphere by a 

 large slit ; foot simple, with an anterior marginal groove, 



OBSERVATIONS. 



The general appearance of the shell resembles much 

 that of a Helix, but the base of the columella is a little 

 prominent, and the locality of the umbilicus is more obvi- 

 ously covered with a callus. But the most striking dilfer- 

 ence is in the animal, which in Helix has the eyes al the 

 tip of the superior pair of tenlacula, whereas in Helicina 

 they are at the exterior base of the only pair ; the opercu- 

 lum of the latter is also a sullicient distinction. 



Lamarck formerly united several species under this genus 

 that he has since very properly separated under the name. 



