258 BULLA. DIPPER. Class VI. 



12. FONTI- Gm. Lin. 3427- Moni. Test. Br. 226. id- 



NALis. Lin^ TV. viii. 126. Sup. g6. 



* B. with an ovate pellucid shell ; spires re- 

 versed, and faint ; aperture ovate-oblong ; 

 length half an inch ; breadth a quarter of an 

 inch. 



Running and stagnant waters. 



13. RIVALIS. Lin. Tr. y'm. \26. Mont. Test. Br. Sup. gj. 



* B. with an oval pellucid shell ; spire reversed, 

 pointed, but little prominent; aperture ovate- 

 oblong ; length half an inch ; breadth a quarter 

 of an inch. 



In streams in Hmyipshire. 



14. HYPNO- Gm. Lin. 3428. Mont. Test. Br. 228. 



^^^' Lin. Tr. viii. 127- 



* B. with an ovate pellucid shell; spire reversed 

 and prominent ; aperture ovate lanceolate ; size 

 of an oat grain. 



In ponds and ditches about London and 

 elsewhere. 



