92 On the Tjcnid and F resh-water Mollusca 



one may be found in the Colne. In a ditch rnnning into this 

 river near Sheep-pen Bridge at times it is very plentiful; hut 

 often for months this ditch is dried up, and then I do not 

 know where to find the snails. 



P. FONTixALis, Linn. — Frequent in all the brooks and 

 streams. 



LiMN.EA PEREGEA, Miill. — Everywhere. 



Var. ovata. — I have never found this form except in the 

 Colne and Stour. Some specimens are very large and not 

 unlike L. auricidarla. 



Var. (icuminata. — I find this also in the same localities as 

 the last. 



Yar. maritima. — Occurs in considerable numbers in the 

 brackish, almost salt, water of the ditches near Wyvenhoe 

 Park, in company with P. a I bus. 



Var. scalanformis. — Frequent in the small drains of one 

 meadow near Birch Hall. There are all the intermediate 

 stages between the normal forms and those in which the 

 whorls of the shell are nearly separated. 



L. AURicuLARiA, Liuu. — In the Stour and also in the Colne, 

 but the intermediate forms between L. pere<ira and this species 

 make it at times difficult to decide to which the varieties 

 belong. 



L. STAGNALis, Liuu. — Frcqucnt in the Stour, and especiallj'' 

 so in some years ; also in ponds in many parts of the district 

 where clay occurs. I never find it on gravel. In some 

 ponds at Wormingford the shells are quite two inches long. 



L. PALusTRis, Miill. — Frequent in ponds on all soils. 



L. TRUNCATULA, Miill. — Commou everywhere. It is difficult 

 to understand how^ this snail exists in shallow roadside 

 puddles which are dry during months in the year. These 

 situations generally produce : — 



Var. minor. — ^Commonly. 



Var. major. — I have found this form in a pond near Bottle 

 End, Stanway, which is never dry, in company with L. 

 pahistiis. 



L. GLABRA, Miill. — Ditches and shallow ponds, abundantly'; 

 especially on gravelly soils. I once found it in a wet spot in 



