PALUDINIDJE. 95 



Dr. Beck tells me that this shell is Nerita globulosa 

 of Miiller : it does not well agree with his description. 

 We have received it from Tarbes in France, from M. 

 N. Boubee, under the name of P. humilis. 



Mr. Alder observes (Mag. ZooL and Bot. ii. 116.), 

 "The Paludina viridis of Turton's Manual (ed. 1. 135, 

 f. 122.) I take to be the young of P. similis (Bithinia 

 ventricosa), judging from specimens in Mr. Clark's 

 cabinet." Most probably this idea is correct, as I 

 have not been able to find any authority for Drapar- 

 naud's species being found in this country ; and it is 

 to be remarked that Turton's account is taken from 

 Draparnaud, and Dr. Turton does not give any habi- 

 tat for the species. M. N. BoubeVs specimen of Pal. 

 viridis proves it to be a Hydrobia or minute Littorina : 

 it has a horny subspiral operculum. 



Mr. Alder also thinks that the Paludina stagno- 

 rum Turton, Man. (ed. 1. 336. f. 123.) may probably 

 be a mere slender variety of P. similis. (Mag. ZooL 

 and Bot. ii. 116.) I think it is much more probably 

 a Littorina, as he considers it the same as Paludina 

 acuta of Drap. In the absence of specimens, it is im- 

 possible to decide ; and, as Dr. Turton does not give 

 any locality, it is even doubtful if the whole account 

 of the species and figures were not derived from Drapar- 

 naud's work. If intended for any British species, it 

 must be Littorina ventricosa, which is common in the 

 ditches with Cardium edule, &c., near Tilbury Fort. 



