OF NOETHUMBERLAND AND DURHAM. 43 



4. L. GLABRA, MYlU. 



LimncBus glaber, Gray, Turt. Man. 242, t. 9, f. 106. 

 Limnetts elongatus, Drap. Hist. Moll. 53, t. 3, f. 3, 4. 

 In ditches and ponds, not uncommon near Newcastle. 



5. L. PEREGRA, Mi'lll. 



Limnceus pereger, Gray, Turt. Man. 233, t. 9, f. 101. 

 Var. Limneus ovatus, Drap. Hist. Moll. 50, t. 2, f. 30, 31. 



In ponds, ditches, and slow streams, very common. 



The numerous varieties of this common species, in form, size, 

 and consistency, are very perplexing to the conchologist. We 

 have got it with a rather strong shell, and the spire much pro- 

 duced, at Redheugh and on Holy Island ; and a curious variety 

 in the opposite extreme has been sent us from Darlington, by 

 Mr. Wm. Backhouse, with a very thin delicate shell, and scarcely 

 any spire. The latter comes very near to the form got by Mr. 

 Thompson in Lough Neagh, which is the Gulnaria lacustris of 

 Leach. 



6. L. AURICULARIA, Lin7i. 



Limnceus auriculai'ius, Gray, Turt. Man. 232, t. 9, f. 100. 

 At Prestwick Car (a small variety). — A. H. In ponds near 

 Darlington. — Mr. W. Backhouse, from whom we have received 

 very fine specimens. 



39. PHYSA, Draparnaud. 



1. P. FONTINALIS, Liim. 



Physa fontinalis, Gray, Turt. Man. 251, t. 9, f. 110. 

 In ponds and ditches, not common. Preswick Car, Gosforth 

 Lake, Mill Stream near Busy Cottage, Ryton, Marsden, and near 

 Stockton. 



2. P. HYPNORUM, Linn. 



Ajylexus hypnorum, Gray, Turt. Man. 255, t, 9, f 113. 

 In ditches and ponds, frequent. 



40. PLANORBIS, Muller. 

 1. P. coRNEUs, Linn. 



Plauorhis corneus, Gray, Turt. Man. 258, t. 8, f 95, 



In a pond in Mr. W. Backhouse's grounds at Darlington. 



a 



