244 TAYLOR: ON HELIX ARBUSTORUM. 



leaves of the Coltsfoot ( Tussilago farfara) and Dock ( Rumex 

 vulgaris).'''' 



Young shells have a thin lip with a slight white internal rib. 



It is stated by authors that many Helices retire in summer 

 and place their heads and the mouths of their shells downwards in 

 the earth when the increase of the shell takes place. I am not 

 aware if this is the case with the present species. 



We have no information as to the length of its life, but should 

 suppose that it may sometimes attain an age of 5 or 6 years. 



Animal. 



The Body is usually of a dark grey, or almost black above, 

 but varies to lavender, dark brown, grey brown, umber, sienna, 

 and occasionally to a delicate fawn. The underside varies from 

 a light slate color to pale yellowish grey. The color of the body 

 does not appear to have any apparent relation to the color of the 

 shell — Ught colored bodies have sometimes dark fuscous shells 

 and vice versa. 



Mantle marked with a few indistinct white specks; tentacles 

 slender, widely divergent, with globular bulbs, and eyes a little 

 above their tips; lower pair widely separated and swollen at tips, 

 about one-third the length of upper pair; foot narrow and slightly 

 keeled at tail with the sides transversely grooved. 



The JAW of this species is described by Moquin-Tandon as 

 2.66 mill, broad, with 4 remote, narrow, parallel ribs, the two 

 middle ones rather prominent, sometimes at the centre there is a 

 fifth slightly visible. In old individuals there are sometimes six 

 ribs. In the specimens I examined which were kindly furnished 

 me by Mr. Butterell of Beverley, — who is a skilful microscopist, 

 and ever willing to give his valuable aid to all desiring it — it is of 

 a somewhat crescentic form with blunt ends, bearing four distinct 

 and prominent ribs, denticulate on both margins, especially the 

 concave one, there are also indications of three other ribs. It is 

 composed of indurated or hardened mucus, and is of a horn 

 color, the minute sculpture is formed of longitudinal, wavy lines 

 which follow the exterior outline, and straight transverse lines 

 parallel with the ribs.* 



*Since writing the above, Mr. Butterell has sent 3 other jaws of this 

 species, which differ so much from the ordinary form that I have figured them. 



J.C.iii., October, 1881 



