94 THE LAND Axto FRESHWATER MOLLUSCA OF DORSETSHIRE. 



the shell ; sutures well defined ; spire tapering ; mouth obliquely 

 oval, forming only about one-third of the length of the shell ; outer 

 lip slightly expanded; inner lip spread on the columella. L.I. 

 B.0.4. 



Var. tincta. Shell shorter and broader, light brown with a 

 purplish mouth. 



Hab. Marshes, ditches and ponds. Hoi well (H. H. Wood.) 

 Wilkes Wood, Langton Matravers -, Stoborough meadows, 

 Wareham (J.C.M.PJ. Var. Dorsetshire (J. Gwyn 

 Jeffreys)-, Chamberlayne's, Bere Regis (J.C.M.P.). 



6. L. TRUNCATULA, Midler, pi. 7. 

 HELIX FOSSARIA, Pult. Cat., Rack, ed., p. 56, pi. 18, f. 17. 



Body brownish-black, lighter beneath, covered with fine black 

 specks. 



Shell conic, slightly ventricose, striae similarly arranged as the 

 former, thin, glossy, solid, semi-transparent, pale horn-colour; 

 whorls five to six, the last large, slightly swollen, forming aoont 

 two-thirds of the entire shell ; spire short and pointed ; mouth 

 occupying one half of the length of the shell; suture extremely 

 deep; outer lip arcuated and projecting; inner lip continuous, 

 reflecte . on the columella. L.0.4. B.O.^. 



Var. minor. Shell much smaller, thinner, and semi-trans- 

 parent, dark horn-colour, marked with stronger and closer longitu- 

 dinal striae. L.U.^85. B.0.166. 



Hab. Banks of slow and muddy rivers, marshes, ditches and 

 moist places ; often coats its shell with mud, it is nearly 

 amphibious, being frequently met with out of the water. 



Dried river course, Whatcombe Park ; marshy places, 

 Chapman's Pool, near Encombe -, ditches, Abbotsbury ; 

 Chamberlayne's, Bere Regis ; river-bank, Bryanston Park 

 (J.C.M.P.). Var. Wilkes Wood, Swanage. 



To this mollusc is attacked the unenviable character of being 

 the chief, if not the only agent, or nurse of the Liver-fluke, 

 Fasciola hepatica, an Entozoa, belonging to a group of the animal 

 kingdom whose mode of propagation is by, what is termed the 

 alternation of generations, that is to say that each individual is 

 unlike its own immediate parents and offspring, but resembles 



