LAND AND FKESHWATEK MOLLUSCA. 331 



marshes around the city ; sometimes very large and fine, though 

 generally the shell is disfigured by an incrustation of mud. 



P. contortus, Linn. — Not plentiful ; in stagnant ditches gene- 

 rally. I have it from near Medley, Sandford-on-Isis, Wolvercot, 

 and near Marston. 



Physa kypnorum, Linn. — Locally abundant ; in grassy pools 

 and ditches between North and South Hinckseys, also near Sand- 

 ford Lasher, Watereaton, near Summertown, and from between 

 the Cherwell and Marston village. I can confirm also Mr. Whit- 

 eaves' locality, "in pools on one side (the west side) of the 

 Abingdon road." 



P.fontinalis, Linn. — Plentiful and generally distributed. 



Limncea peregra, Mtiller. — Very common everywhere. 



Var. ovata. — Common, of large size, in the canal. 



Var. amminata. — In a ditch communicating with the Cherwell. 



L. auricularia, Linn. — Plentiful, though perhaps somewhat 

 restricted in range. Very fine in canal above Wolvercot, also at 

 North Hincksey and near Iffley. In March, 1881, when the rivers 

 and streams were very low, many of this species were left high and 

 dry in various parts, and in nearly every shell the occupant was 

 being devoured by one or more large water leeches. 



L. stagnalis, Linn. — Plentifully and generally distributed. 



Var fragilis. — Occurs in the canal. 



L. palustris, Miiller. — Plentifully and generally distributed ; 

 the specimens in the Museum Collection are rather larger than 

 usual. 



L. truncatula, Miiller. — Plentiful on muddy banks above the 

 water's edge along the rivers, streams, and canal. 



Ancylus lacustris, Linn. — Plentiful on the larger water-plants 

 in slow-flowing and stagnant water. On the approach of winter 

 this mollusk crawls down below the surface of the mud, between 

 the sheathing leaves of Iris, Sparganium, and similar plants, for 

 the purpose of hybernation. 



A.fluviatilis, Miiller. — On and under stones in the River 

 Evenlode : this tributary falls into the Isis just below Eynsham 



Bridge. 



(To be continued.) 



