144 HELICID^, 



This mollusc is hardy, but somewhat sluggish. Linne 

 was under the impression that it has the power of 

 boring into calcareous rocks, and consequently gave it 

 the specific name of lapicida (lapidary). He says of 

 it, " ut larvse lignum sic calcem rodens " (eating into 

 chalk as caterpillars do into wood), and though the 

 immortal Swedish naturalist was undoubtedly in error 

 in this respect, the name lapicida is, after all, by no 

 means inappropriate, as anyone who knows what a 

 lapidary's wheel is like will readily allow, the shell 

 with its sharp keel bears a strong resemblance to it. 



Var. I. rt/i^/;m.— Shell white. Went Vale, Yorkshire (Hebden), 

 Reigate (Saunders). 



Var. 2. iniiior. — Shell smaller and of a darker colour. 



24. H. OBVOLU'TA,* MtJLLER. PL. VIII. 



Body narrow, rather truncate in front, light reddish-brown 

 above, pale greyish-brown below, very slightly transparent, 

 tubercles oblong, placed in thick-set lines, brown finely powdered 

 with white ; tentacles very long, slender, but slightly thickened 

 at the base, dusky-brown or reddish-brown, bulbs globular; 

 upper tentacles near together at the base, closely granulated ; 

 lower pair somewhat diverging ; foot with a narrow milk-white 

 border, and ending in a slender and keeled tail ; lingual ribbon 

 with 170 rows of 91 teeth = 15,470. 



Shell subdiscoidal, compressed, rather solid, nearly opaque, 

 of a dull aspect, rufous-brown, with fine, close-set stride in the 

 line of growth ; periphery rounded ; epider?nis thick, covered 

 with numerous strongish, rufous-brown hairs ; whorls 6|, very 

 gradually increasing ; spire depressed below the level of the body 

 whorl, apex smooth, glossy ; stitnre deepish ; month bluntly 

 triangular in consequence of two protuberances, one of which 

 is placed slightly alDove, and the other below the periphery ; 

 outer lip pinkish-white, thick, considerably reflected ; umbilicus 



large and deep. 



* Wrapped up. 



