5612 Molluslcs. 



from some author, but I cannot recal to mind from whom they came. 

 Mr. Whiteaves also says of this beautiful shell, " Very rare. I have 

 taken one fine specimen from a clear brook communicating with the 

 river, on the right hand side of the path between the Railway Lake 

 and South Hincksey. Mr. Baxter has informed me that the late 

 Mr. Miller, of Bristol, found it at Godstow. I have repeatedly searched 

 for it there, but have always failed to find it." 



Planorbis imbricatus. Many specimens among the Weston-on-the- 

 Green shells. Mr. Strickland met with this species in a pond near 

 Henley. 



„ laevis. Mr. Stretch's list. I wrote to Mr. Stretch to 



inquire about this and two or three other species : he tells me that 

 " the specimens were collected some years ago by a friend in the 

 town ; he believes them to be what they are called, but has not met 

 with them himself," Stretch in Hit. 



Cyclas lacustris (C. caliculata, Drap.). Weston-on-the-Green ; 

 among Mr. Matthews' shells. "Ponds at Fawley," Strickland. 

 Hanwell, Stretch. " Very local ; found abundantly in a railway lake 

 at Wolvercot, chiefly at one end, which is choked up with a profuse 

 growth of Ceratophyllum demersum. It also occurs in peaty pools 

 near Headington Wick Copse, in which the prevailing plant is Chara 

 hispida," Whiteaves. 



Pisidium obtusale. " A stream at Botley," Whiteaves. 



„ pulchellum. Specimens from Weston-on-the-Green ; and 

 I also took a few in the Woodeaton Brook. " Not uncommon in 

 gravelly ditches. A good locality for it is a ditch near Cowley, in 

 which Samolus Valerandi grows," Whiteaves. 



„ nitidum. " Very rare. I have taken two specimens from 

 a ditch near Summertown, communicating with the Cherwell, in 

 which Ranunculus lingua and Utricularia vulgaris grow," Whiteaves. 

 Mr. Stretch informs me that this Pisidium was inserted in his list of 

 Banbury shells by mistake, as was also Pisidium cinereum, vide 

 "Correction of an Error" (Zool. 4635). 



A few words must be said respecting Unio pictorum, which is 

 contained in the catalogues of Mr. Strickland and Mr. Stretch. 

 Mr. Whiteaves says, in reference to Unio tumidus, " Both Mr. Strick- 

 land and Mr. Stretch have mistaken this for Unio pictorum." I do 

 not know the grounds on which Mr. Whiteaves bases this positive 

 assertion : the following reasons have, however, always led me to 

 think that such a mistake may have been made: — 1st. Neither of 

 these two lists contain Unio tumidus, which is certainly common in 



