136 PAPEIJS, ETC. 



Farn. UNIONIDiE. 

 Genus U^'IO. Eetzius. 



U. pictorum, Linna3'as. Mya pictorura, Mut. and Rack., 

 Trans. Linn. Soc, vol. viü., p. 38. " The Kennet and 

 Avon.'" — Forbes and Hanley. We have never seen speci- 

 mens, but are infovmed by Mr. Eussell, of tlie Bath 

 Literary Institute, that the species is very common in the 

 Avon. 



U. tumidus, Retzius. " The Unio of the river Avon and 

 of the Kennet and Avon Canal is the typical U. tumidus 

 Avith its black skiu, and the flatter varieties rayed with 

 yellow and green. Twenty ycars ago, after a flood, I met 

 ■\vith it about two miles from Bath, cast in large quantities 

 on a river-side meadow; but I have seen none since." — ]Mr. 

 AYm. Clark, in litt. "The Avon and the Kennet."— 

 Forbes and Hanley. 



Genus Asodonta, Brugiere. 

 A. ci/gnea, Linna;us. Mytilus anatlna, Mat. and Rack., 

 Trans. Lin. Soc., vol. viü. Common. The variety 

 Avonensis (Mytilis Avonensis, Mont. Test. Brit., p. 172) 

 was found, we believe, in the Salisbury and Hampshire 

 Avon, not the Bath and Bristol river, 



Fam. MYTILID^. 

 Genus Dkeissena. Vau Beneden. 

 D. polymorpha, Pallas. The late ISlr. Hugh Strickland, 

 in a paper, published in Loudon's Mag. Nat. Hist., new 

 series, voh ii. (1838), p. 361, on the "Naturalisation of 

 Dreissena in England," states that " this shell has lately 

 been 'planted' by Mr. Stutchbury, of Bristol, in some 

 waters near that place." So prolific a species once planted 

 is hardly likely to have become extinct. 



