150 PNEUMONOBRANCHIATA. 



as wide, with a white rib on the inside ; umbilicus 

 moderately large and deep. 



According to the observations of Mr. Jeffreys, this 

 animal feeds on the Jungermannia platyphylla. It has 

 a very extended range, for it is found in the north of 

 Sweden. 



34. 16. Helix lamellata. Scarborough Snail, (t. 5. 

 f. 48.) Shell somewhat trochiform, grey ; the peri- 

 ostraca rising into close-set equal longitudinal 

 lamellse ; whorls six, gradually increasing in size ; 

 mouth lunate ; umbilicus deep. 



Helix Scarburgensis. Turton, ed. 162.; Alder, 

 Cat. 109. 



Helix holosericea. Miller, MSS. 



lamellata. Jeffreys, Linn. Trans, xvi. 333. : 



not H. lamellosa Ferussac. 



Inhab. woods, north of England — Scarborough 

 (Bean), Newcastle (Alder). 



Animal pale grey. 



Shell the tenth of an inch in diameter, and as much 

 high, grey or pale horn-colour, semitransparent, pyra- 

 midal, with very numerous regular longitudinal 

 lamellae not shooting in the middle into spinous pro- 

 jections ; spire composed of six rounded and deeply 

 divided volutions, which very gradually decrease from 

 the tumid and rounded base; the tip obtuse and 

 usually of a whitish colour ; aperture narrow crescent- 

 shaped, wider than long, the margin thin and reflected 

 over the umbilicus, which is small and deep. 



Like that of H. aculeata, the periostraca of this 

 species rises into thin laminar foliations, which in 

 various positions of light reflect a velvety or satin-like 



