44 CATALOGUE OF THE MOLLUSCA 



2. P. ALBUS, Mull. 



Planorhis alhus, Gray, Turt. Man. 259, t. 8, f. 97. 

 In ponds and slow streams, frequent. 



3. P. L^vis, Alder. 



Planorbis Icevis, Aid. in Newc. Nat. Hist. Tran. ii. 337, 

 Gray, Turt. Man. 261, t. 12, £ 148. 

 In ponds at Whitley Quarries, and on Holy Island. 



4. P. NAUTiLEUS, Linn. 



Planorbis irnbricatus, Gray, Turt, Man. 261, t. 8, f, 94. 

 In ponds, frequent. 



5. P. CARINATUS, Iliill. 



Planorbis carinatus, Gray, Turt. Man. 262, t. 8, f. 89. 

 Rare. Near Stockton. — Mr. W. Backhouse. 



6. P. UMBILICATUS, Miill. 



Planorbis complanatus, Aid. in Newc. N. Hist. Trans, i. 31. 

 Planorbis 7narginatus, Gray, Turt. Man. 265, t. 8, f. 87, 88. 

 In ponds and ditches, not common. Prestwick Car, Ryton 

 Haughs, and near Stockton. 



7. P. spiRORBis, Linn. 



Planorbis sjiirorbis, Gray, Turt. Man. 268, t. 8, f 98. 

 In ditches, common. 



8. P. NITIDUS, Miill. 



Planorbis nitidus, Gray, Turt. Man. 268, t. 8, f. 93. 

 Rather rare. In ponds at Redheugh. Benwell engine pond. 

 — W. Sutton. Near Middleton-one-Row and Stockton. — J. A. 



9. P. CONTORTUS, Lin7i. 



Planorbis contortus, Gray, Turt. Man. 270, t. 8, f 96. 

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

 Lake, Ryton Haughs, near Wooler, and near Stockton. 



41. ANCYLUS, Geoffroy. 



1. A. FLUVIATILIS, Miill. 



Ancylus fluviatilis, Gray, Turt. Man. 249, t. 10, I 125. 

 On stones in rivulets, common. 



2. A. LAOUSTRIS, Miill. 



Velletia lacustris, Gray, Turt. Man. 250, t. 10, f 126. 

 On aquatic plants in ponds and ditches, not common. Prest- 



