By E. W. Sivanton, 81 



var. ovalis (Moutagu). — ''This very strong variety is not 

 uncommon in the Avon that runs through the north of "Wiltshire 

 and Somersetshire, inhabiting the deeper parts of the river "(=Mya 

 ovalis, Test. Brit., pp. 34 and 563). From the Avon and Froome, 

 Wiltshire (Turton, as Mysca ovata). 



Anodonta cygnaea (Linne). — Widely distributed in the canal, 

 and occurs in all the largest ponds. Numerous in the canal at 

 Trowbridge, canal at Devizes, the moat at Britford, Longleat (Vize) ; 

 canal at Wantage (Bromehead) ; canal at Devizes (Heginbothom) ; 

 Stourton ponds and Longleat (E. W. S.). 



var. incrassata (Sheppard). — This shell we found in great 

 abundance in the Biver Avon about Lackham " (=Mytilus 

 avonensis, Test. Brit., p. 172). " Miss Bennett, of Norton House 

 favoured me lately with specimens from Tisbury, Wiltshire. They 

 were old shells, and the animal having lived in water highly im- 

 pregnated with chalk and calcareous matter, its epidermis has been 

 secreted so rapidly and increased the shell so much in thickness 

 that the Linnean character ' testa fragilissima ' is entirely lost " 

 (Gray's Turton, p. 292). Specimens from the Norton House 

 garden pond, labelled " grown to this size by good living," may be 

 seen in the Cunnington Collection at the Devizes Museum. Mr. 

 J. W. Taylor remarks : "A characteristic specimen of this variety 

 from a brook at Tisbury, Wiltshire, kindly given to me by the 

 late Mr. J. Pickering, weighs 2,227 grammes, or 512 ounces, while 

 an example of the typical form of equivalent size from Nagden, 

 near Faversham, collected by the late Miss E. B, Fairbrass, weighed 

 only 322 grains, or about one-seventh the weight of the variety 

 incrassata" (Mon. L. & F. W. Moll, i., 79). 

 Sphaerium rivicola (Leach). — Locally abundant. " Frequently 

 i to be found at certain seasons in the canal at Trowbridge, Milford 

 near Salisbury, canal at Devizes " (Vize); Devizes (Miss Cunnington 

 and Heginbothom) ; Salisbury Avon (E. W. S.). 

 Sphazrium corneum (Linne). — A common species. Canal at 

 ' Trowbridge (Vize) ; Great Bedwyn (Townsend) ; Swindon (Cock- 

 ! erell) ; Devizes (Miss Cunnington and Vize) ; ponds at Stourton, 

 i and Avon at Salisbury (E. W. S.). 



i VOL. XXXVI. — NO. CXI. G 



