250 HELlCID.f:. 



and irregularly, but closely, striate in the line of growth : 

 periphery rounded : epidermis thin : ivJwrh 6-7, convex, but a 

 little compressed, the last equal to about one-third of the shell, 

 the two first whorls much smaller in proportion to the rest : 

 qyire short, abruptly and bluntly pointed : suture rather deep : 

 mouth forming an oblique segment of about two-thirds of a 

 circle, furnished sometimes with a small tubercular tooth on 

 the columella, which is placed nearly in the middle ; inside 

 shghtly tinged with reddish -brown : outer lip sharp, strength- 

 ened by a thick, white, exterior rib, which is placed at a little 

 distance from the margin ; outer edge slightly reflected : inner 

 lip spread on the pillar : umbilicus small and shallow, contracted 

 by a slight ridge or crest at the base of the shell. L. 0-133. 

 B. 0-6. 



Var. 1. higranata. Shell rather smaller and thicker, and 

 having a tubercular tooth or denticle considerably within the 

 outer lip, as well as that on the columella. P. higranata, 

 Rossmassler, Iconogr. ix, x. p. 27, f. 645. 



Var. 2. alhina, Menke. Shell white. 



Habitat : Under stones^ at the roots of grass, and 

 among dead leaves, everywhere from the Moray Firth 

 district to Guernsey, especially on the sea-coast. Var. 1 . 

 Bath (Clark) ; Lnlworth, Dorsetshire (J. G. J.) ; Ox- 

 fordshire (Whiteaves) ; Weston-super-Mare (Norman). 

 Var. 2. Somersetshire (Clark, Norman, and J. G. J.) ; 

 Oxfordshire (Whiteaves). I have also found a monstro- 

 sity in whichL the lower whorl is furrowed, and another 

 which has the periphery keeled, — the former ha\dng been 

 apparently caused by a grain of sand adhering to the 

 mantle while the shell was in course of formation, and 

 the latter by an accidental fracture of the last whorl, which 

 obliged the animal to make a new mouth and to shorten 

 the base. As an upper tertiary fossil it is very common, 

 and often indicates the former presence of littoral con- 

 ditions, as this species not only peculiarly affects sandy 

 shores and maritime places, but is also Avashed down in 

 gi-eat numbers by estuarine rivers and thrown up on 



