HUDSON: Hogg's list of mollusca of Stockton. 259 



17. Tellina rivulis, Lin. Trans. 1 River Tellen. 



Tellina amnica, Lin. Gmel. J Don., vol. ii., t. 64, f. 2. 



This species occurs sparingly in the same rivulets with 

 the horny Tellen. [This is Pisidiuvi a))inician?\ 



18. Unio pictorum, Drap. ) „ • . j i 

 -n^ , r, to: Painters muscle. 



Mya pidorum, Lm. Syst. > p. 1 "" t s 



Mya ovalis, Don. j "' ' •' ■ y- 



In the ponds at Wynyard, Mr. W. C. Trevelyan. 



[This record of Unio pictorum is quoted by Dixon 

 and Watson (Mr. Watson, a native of the district, however, 

 never confirmed it) also in Alder's Cat., 1848. 



I have visited Wynyard with a view to confirming this 

 but without success, and am inclined to think Sir W. C. 

 Trevelyan has been mistaken in his species, which might 

 possibly have been Anodonta cygnea var. rostrata, a variety 

 or approaches to which I have met with close to Wynyard. 

 — B. H.] 



19. Unio margaritifer, Drap. I River pearl muscle. 

 M)'a nia7-garitifera, Lin. Syst. j Don., vol. iii., t. 73. 



Da Costa mentions that this muscle inhabits the Tees. 

 J. H.has found it in great plenty in the small River Browney, 

 near Bearpark, about three miles to the north-west of 

 Durham. Linn^us says, " habitat in totiiis orbis arctici 

 cataractis." 



[Is not Da Costa's species more likely to be Mya 

 arenaria, common at the Tees' mouth ? I have not seen 

 his notice. I have visited Bearpark this year, and very 

 carefully worked the stream from a mile above Bearpark 

 to a mile below the same place, but could find no signs of 

 this species. The bed of the stream and the current would 

 be favourable to the mussel, but since Mr. Hogg's time 

 many collieries have been opened in the valley and their 

 pumpings and waste water may have to no small extent 

 affected the water and rendered it unfit for the reproduction 

 of the species. The poisoning of the water has certainly 

 materially reduced its value as a trout stream since I was 

 a boy.— B. H.] 



