114 THE LAXI) AND FRESHWATER MOLLttSCA Ofr DORSETSHIRE. 



and irregular strias; whorls six, the last occupying about three- 

 fifths of the shell: spire almost flat; suture deep; mouth very 

 oblique, round with a slight inside rib, white or reddish; umbilicus 

 large and open. L.0.25 B.O.G75. 



Var. alba. Charpentier.'ShvM milk-white. 

 Hab. Dry heaths, downs, on shrubs and plant?. Gener- 

 ally distributed. Var. Pastures, Kimmeridge Hill (J.C.M.P.). 



16 H. ROTUND ATA, MulUr, pi. 9- 



HELIX KADIATA, Pult. cat., p. 47., Rack, ed., p. 54, pi. 20, f. 15, 



16. 



Body rounded in front, obtusely pointed behind, greyslate-colour 

 or brown, svith a tin^e of blue, marked with black specks on the 

 sides and tail. 



Shell depressed, especially beneath, rather thin, not very glossy, 

 yellowish-brown or horn-colour, with transverse streaks of reddish 

 brown; extremely fine, slightly raised ribs above and below, except- 

 ing the first whorl, which is destitute of ribs ; whorls six to seven, 

 the last occupying about one-third of the shell, keeled ; spire slightly 

 raised ; suture deep ; mouth obliquely quadrangular, with a flesh- 

 coloured or white rib inside ; umbilicus very large and deep. L.O.I. 

 B.0.275. 



Hab. Under stones, logs of wood, and bark of old trees, 

 moss, &c. Generally distributed. Quaternary deposit, Blasher- 

 well. 



17. H. RUPESTRIS, Studer, pi. 9. 



HELIX UMBILICATA, F. and IT., vol. iv.. p. 81, 6,7, 8; Pult. cat., 

 Rack, ed., p. 54. pi. 19, f. 24 ; Mont. Test. 

 Brit., p. 434, pi. 13, fig. 2. 



Body round in front, narrowing towards the tail, dark slate-colour, 

 or reddish, covered with small, scarcely raised tubercles. 



Shell subconical, more convex above than below, thin, fragile, 

 slightly glossy, dark-brown or horn-colour, marked longitudinally 

 with extremely tine, irregular, nearly defaced striae ; whorls five, the 

 last only keeled when young; spire raised, summit glossy ; suture 

 deep ; nioutJi oblique, rounded, horse-shoe shaped ; umbilicus large, 

 often exposing the interior of the spire. L.0.075. B.O.llo. 



Hab. On rocks, walls, and stones. Under loose stones in 

 Portland, and on the top of Corfe Castle, Montagu. Very 

 abundant in Purbeck, there is not a stone wall throughout the 

 district, which is not the resort of this little mollusc ; Puncknoll 

 (J.CM-P.). 



