LAND AND FRESH WATER MOLLUSCA OF THE EAST RIDING. I 29 



Omitting Helix lapicida and Azeca tridens, which are 

 included in the Census, but of which no record has been 

 found, 100 species have been recorded for the Riding. 

 These are distributed as follows : — 



77 



82 



65 



Derwentland only : (2), Viviparus contectus, Spluerium 

 rivicola. 



Wolds only : (7), Limax cinereo-niger, L. marginatus, Amaha 

 sowerbyi, Testacella scutu/um, Clausilia laminata, 

 Pupa anglica, Hyaliuia lucida. 



Holderness only : (8), Amalia gagates, Testacella haliotidea, 

 Balea perversa, Vertigo minulissima, Segmentina 

 nitida, Limncea glutii/osa, Paludestrina jenkinsi, 

 Phidium milium. 



Derwentland and Wolds : (2), Helix granulata, Clausilia 

 rugosa. 



Derwentland and Holderness: (8), Viviparus viviparus, 

 Bythinia leachii, Neritiua fluviatilis, Unto tumidus, 

 U. pictorum, Auodonta anatina, Pisidium amnicum, 

 P. hensloivanum. 



Wolds and Holderness: (8), Arion subfuscus, A. intermedins, 

 Agriolimax lievis, Helix itala, H. pygmcea, Vertigo 

 antivertigo, Planorbis jontanus, SphcErium lacustre. 



Initials only, without references, are used to indicate 

 records in the tabulated lists, thus :—" W.C.H." refers 

 to Mr. Hey's paper in the Journal of Conchology ; 

 "W.C.H. in R.M.C." refers to a record by Mr. Hey 

 included in Mr. Christy's list ; and "W.C.H. circular 62" 

 to one on the Yorks. Naturalists' Union excursion circular 

 bearing that number. "Y.N.U. 1883" signifies that 

 the species was found on the East Riding excursion for 

 that year, and is included in the report of such excursion. 

 Records initialled "T.P." have not been previously 

 published. 



