3/8 



ON THE GEOGRAPHICAL DISTRIBUTION OF 

 MOLLUSCA IN SOUTH LONSDALE. 



Rev. C. 



E. Y. KENDALL, B.A., J. DAVY DEAN, and 

 W. MUNN RANKIN, M.Sc, B.Sc. 



[Continued from page 3S9)' 



Neyitiiia is a true non-calcareous species, while Ancylus 

 occurs in both calcareous and non-calcareous rivers, and can 

 exist in shallower and swifter streams than the former. L. 

 aiiyiciilaria is rare, and is of a small acute form. Unio mar- 

 garitifer is local, but abundant in the deeper pools of the lower 

 river. This interesting species is characteristic of a northern 

 fauna, its range extending from the Conway and Dee throughout 

 the north-western counties into Scotland, right into the High- 

 lands. It is a favourite food of the otter, and seems to abound 

 in rivers where this animal is common. 



(c) The Smaller Rivers (Example — R. Bela.) 



Open Water. 



L. pereger Miill. 

 Neritina fliiviatilis L. 



Marsh. 



Reed Belt. 



Planovbis carinatus Miill 

 Bithynia tentaculata L. 



This is a much slower moving river than the Lune, and shews 



interesting features. In the reaches examined Ancylus was 



absent. Limncea pereger and Planorbis carinatus seem plentiful. 



The latter is a southern and eastern type, and is only local in 



the north-western counties. This is the only locality for it in 



Lonsdale. 



Note. — We have no records for the marsh section of these 

 non-calcareous streams. Captain Farrar gives the following 

 for the margins of the becks of the Lake District, which note is 

 of interest, and may apply to the examples already taken. 



Open Water. 



L. pereger Miill. 

 Ancylus fluviatilis Miill. 



Marsh. 

 Agriolimax Icevis Miill. 



Hygromia fusca Mont. 

 Pupa anglica Fer. 



He states that H. fusca occurs ' wherever sedges border the 

 swiftly-running becks.' Pupa anglica is a moss feeder, and 

 though occurring often in woods, this may be its true position. 



5. Heath Moors. 



§ I. — Lowland : Ditches and pools on the mosses. 



Open Water. . 

 LimncBa pereger Miill, 



Reed Belt. 



himncea palustris 



Miill. 



Marsh. 



Planorbis spirorhis L. 

 Pisidium nhtusale Pf. 

 'Rd.re\jAplecta hypnorum. 



Naturalist, 



