246 TAYLOR : ON HELIX ARBUSTORUM. 



Shell. 



Shell, globular, somewhat compressed beneath, brownish 

 horny, freckled with opaque yellowish or reddish markings, with 

 a single brown band encircling each whorl, about its upper third; 

 strongly and irregularly ridged in the lines of growth, and finely 

 striate in a spiral direction; epidermis rather thin; whorls 5 — 6, 

 convex, the last occupying three-fifths of the shell; spire generally 

 depressed and blunt; suture rather deep; mouth forming about 

 two-thirds of a circle; outer lip, thick, white and reflected, some- 

 times strengthened by a slight internal rib, much inflected above 

 and rounded beneath; inner lip, a mere film; umbilicus small and 

 oblique, nearly concealed by a fold of the outer lip. Diam. maj. 

 24, min. 20, alt. 16. 



Epiphragm very thin and transparent, sometimes iridescent. 

 The respiratory orifice is near the upper part and nearly close to 

 the outer wall, and is strengthened by a deposit of carbonate of lime. 



Variations. 



The differences in form, color, size, substance and texture of 

 this species has caused authors at different times to differentiate a 

 number of the most striking variations. Opinions differ widely 

 as to the range of variation of this species, some of our analytical 

 conchologists regarding as different species the forms considered 

 as varietal only by those taking broader views. 



Var. major Pfr. Shell larger. Diam. maj. 30, min. 27, alt. 20 mill. {=var. 



depressa Scholtz). 



I have included under this head the var. depressa of Scholtz, 

 which only appears different in being a very little smaller. 



Dr. Jeffreys says 'not very uncommon'. Mr. C. Ashford has 

 found it on the Castle Holmes at Scarbro' and Mr. Blackburn at 

 Knaresbro'. Pfeiffer records it from Monte Monchsberg, Salzburg, 

 and I have found it on the shores of Lake Lucerne in Switzerland. 



Var. septentrionalis Clessin. Shell medium size, spire depressed, thin, um- 

 bilicated. Diam. 19, alt. 14 — 15 mill. 



Inhabits Medalpad, Sweden.* 



J.C, iii., October, 1881 



