Mollusks. 3763 



Limnseus pereger. Very common. 



„ „ var. ovatus, Drap. A ditch near West Hinksey. 



„ „ var. acutus, Jeffreys. In the ditch running along 



the side of Cowley Marsh. 



„ stagnalis. Very abundant and large. 

 „ „ vax.fr ay Ms, Mont. In ditches at West Hinksey. 



„ palustris. Common in ditches, West Hinksey and Port 

 Meadow. 



„ truncatulus. On the mud of the banks of the Isis. 

 Ancylus fluviatilis. Not common ; in the Cherwell, on stones and 

 on shells of Anodon cygneus and Unio tumidus. 



Velletia lacustris. I have found this species only in one ditch, — 

 that on the right hand side of the foot-path leading from Oxford to 

 West Hinksey, on submerged leaves of Nuphar lutea. It is curious 

 that I did not find a single specimen on the leaves of Nymphaea alba, 

 which was growing in the same ditch ; was this merely accidental ? 



Physa fontinalis. In many of the ditches in the neighbourhood ; 

 particularly fine in the same ditch with Velletia lacustris. 



Aplexus hypnorum. Very local ; ditch at the foot of Bullingdon. 

 Planorbis corneus. Very abundant; very fine in the Cherwell, 

 where it passes St. Clement's. 



„ albus. Not common ; ditches at West Hinksey and the 

 river Cherwell. 



„ carinatus. Rather common ; Hinksey, Port Meadow and 

 Christchurch Meadow. 



„ marginatus. Very common. 

 „ vortex. Very common. 



„ spirorbis. Ditch at the side of Cowley Marsh. 

 „ nitidus. Two or three specimens in a ditch in Christ- 

 church Meadow. 



Cyclas rivicola. Very common in the river Cherwell. 



„ cornea. Found in most of the ditches. 

 Pisidium pusillum. Ditch at the foot of Bullingdon. 



„ Henslowianuui. Very rare ; two specimens in the river 



Cherwell. 



„ amnicum. Cherwell, and ditch in Christchurch Meadow. 



Anodon cygneus. Common; the Cherwell and many of the ditches. 

 „ „ var. rostrata, Kokeil. One specimen in the river 



opposite Port Meadow. 



Unio tumidus. Abundant in the Cherwell. 



Dreissena polymorpha. A few specimens in the Cherwell. 



