THE LAA T D AND FRESHWATER MOLLUSCA OF DORSETSHIRE. 107 



narrow; outer Up curved and reflected on the pillar; umbilictis 

 indistinct. L.O.I. B.O.I. 



Hab. Among moss, under stones and decayed timber in 

 woods and shady places ; Wilkeswood Farm, Langton 

 Matravers (Smith) ; among moss, Whatcombe Park ; Houghton 

 Wood (J.C.M.P.). 



Genus IV. HELIX, Linn. 



Body rather long, capable of being contained within the shell ; 

 mantle thick, slightly bilobed on the under side; tentacles four, 

 cylindrical, enlarged at their summits ; foot elliptical. 



Shell globular, or subcom pressed, rarely flat; spire generally 

 short, the last whorl more or less the largest ; mouth forming an 

 oblique segment of a circle, rarely round or triangular; outer lip 

 thin or thick, sometimes strengthened by a rib, or reflected ; umbili- 

 cus usually distinct and more or less open, but in a lew species quite 

 closed or wanting, except in the young state. 



I. HELIX ACULEATA, Linn., pi. 8. 



HELIX SPINULOSA, Pult. cat., Rack, ed., p. 54, pi. 19, fig. 23. 

 Robinson's Purbeck, p. 178. 



Body thick and short, narrowing at both extremities, more 

 rounded in front, where it has a brownish tint, the rest of the body 

 greyish slate-colour. 



Shell globose-pyramidal, slightly convex beneath, with oblique 

 projecting plaits, which rise in the middle of each whorl, termin- 

 ating in a compressed hooked point, thin, not glossy, transparent, 

 horn-colour ; whorls lour to four-and a-half, convex, gradually 

 increasing ; spite obtuse ; suture deep ; mouth forming a deep arch ; 

 outer lip slightly thickened, with a white rib and reflected in adult 

 specimens; inner lip slightly reflected over th ; umbilicus, which is 

 narrow and small. L.O.I. B.O.I. 



Hab . Among dead leaves and moss in woods ; Spettisbury, 

 Rev. T. Rackett ; Marble Quarry, Wilkeswood Farm, Leeson 

 Wood, Langton Matravers (Smith) ; East Lulworth (Kendall). 



2. H. POMATIA, Linn., pi. 7., pi. 9. 



Pultcat.,^. 47., Rack, ed., p. 54. pi. 20, f. 14, Cochlea poma- 

 tia, Da Costa, Brit. Conch., p. 67, pi. 4, fig. 14. 



Body obtusely rounded in front, terminating behind in rather a 

 sharp point, yellowish-grey, sometimes with a greenish tinge, 

 covered with large contiguous, prominent tubercles, principally in the 

 region of the neck. 



