38 IIELICIDJ5. 



increase. Sj^ire very little raised ; apex bluut. Whorls 

 three and a half to four, moderately broad, gradually but 

 not abruptly enlarging, but little convex, somewhat oblique, 

 well defined, the last shelving. Aperture very oblique, 

 rounded, crescent-shaped, broader than high, nearly as 

 wide as half the total diameter. Peristome thin, simple, 

 not reflected. Base a little flattened, umbilicus deep, rather 

 large. Diameter about the fifth or the sixth of an inch. 



The animal is white with two black cervical lines. It 

 varies in being darker. The cloak is white speckled with 

 black (Alder). It is most frequent in woods in the north 

 of England, where it was first noticed by Mr. Alder in 

 the neighbourhood of Newcastle. 



Z. RADiATULus, Aider. 



Very small, depressed, shining, of a transparent, pale amber 

 colour^ rarely white, on both disks, regularly striated ; whorls 

 at most four, flattened at their junction with the inner ones ; 

 body whorl decidedly broader than the preceding turn ; um- 

 bilicus moderately large. 



Plate CXXI. fig. 1. 



Ihlix radiatula. Alder, Trans. Nat. Hist. Soc. Nortlnimb. vol. i. p. 3B ; and 

 vol. ii. p. 340. — Jeffrev.s, Trans. Linn. Soc. vol. xvi. p. 511. 

 — Thompson, Ann. Nat. Hist. vol. vi. p. 35. — Brown, 

 Illust. Conch. G. B, p. 53. 



Zonlles radkUuhis, Gray, Manual L. and F. W. Shells, p. 173, pi. 12, f. 137. — 

 Macgil. Moll. Aberd. p. 91. 



Hdiwjnini, var. /S. Pfeif. Monog. Helic. vol. i. p. 96. 



Small, depressed, thin, transparent, shining, of an uni- 

 form brownish amber-colour or fulvous horn-colour (rarely 

 pure white), not becoming white or opaque underneath, 

 with regnlar sharply cut longitudinal striae upon the su- 

 perior disk, which are much arcuated, numerous but not 



