3o6 JOURNAL OF CONCHOI.OGY, VOL. 12, NO. II, JULY, I909. 



Limnaea pereger (Miiller).— Occurs all over the district abund- 

 antly, and is very variable both in size and condition. Sinistral 

 specimens, labelled "Scarborough," are in the British Museum of 

 Natural History. Bean called this form a separate species, L. Uneatus. 



Both long and short-spired forms occur, and vars. ovata, obloftga, 

 and succiiiecBfoDnis also can be obtained. 



Limnaea palustris (Miiller). — Very common. Scarborough 

 iNTere, Throxenby Mere, Cayton Bay; ditches at Folkton, Flixton, 

 Willerby, and Cayton ; fine on cliffs near Filey. 



var. elongata Moquin-Tandon. — Seamer Carrs, one. 



var. conica Jeffreys. — Seamer Carrs. 



var. roseolabiata Jeffreys. — Common with type. 



Limnaea truncatula (Miiller). — Occurs on and near the cliffs, 

 from Cloughton to Speeton Cliffs in ponds, marshes, and streams, 

 occasionally in drinking troughs. 



var. microstoma Drouet. — North Cliff. 

 Limnaea Stagnalis (Linne). — Formerly very fine in Scarborough 

 Mere, now probably exterminated ; common in pond in Cayton Bay, 

 and rarer in ditches on Seamer and Folkton Carrs ; Rivers Hertford 

 and Derwent. 



var. fragilis Linne. — Pond on Filey Road, now drained. 



Limnaea glabra (Miiller). — Pond in Cayton Bay, now extinct; 

 Langdale End and Harwood Dale, rare. A remarkably decollate 

 form has persisted many years in a small marsh frequently dry in 

 Lady Edith's Drive, along with small typical form. 



m. sinistrorsum. — One in Lady Edith's Drive (y. of Cofich., 

 vol. 12, p. 191). 



Amphipeplea glutinosa (Miiller). — There are specimens in 

 Scarborough Museum said to have been taken in the Valley, but no 

 trace of this species is now to be found. 



Planorbis corneus (Linne). — Castle Hill, Scarborough Mere, 

 ditches Seamer and Folkton Carrs, rare ; River Hertford, pond on 

 Seamer Moor, introduced. 



Planorbis albus Miiller. — -Widely distributed, but not usually 

 very common. Castle Hill, Scalby, Hackness, ^^"ykeham, Derwent 

 at Ayton, and Sherburn, Folkton and Seamer Carrs. 



Planorbis glaber Jeffreys. — Observed in only one shallow pond 

 at Suffield. Abundant on Elodea canadense. It has the characteristic 

 transverse markings. A scalariform specimen was obtained in 1901. 



Planorbis crista (Linne). — Abundant where it occurs. Scar- 



