80 TSfi LAJfD ASD fKfi6HWAT4& AOLLtfeCA Of DOB6ET8EIBE. 



sometimes with some darker zones, and often with a whitish, or yel- 

 lowish band, more or less marginal ; anterior and posterior sides 

 rounded, the latter rather more produced ; beaks prominent ; liga- 

 ment short, scarcely visible from the outside j muscular and palliat 

 scars weakly marked. L.0.3. B.0.4. 



Hab. Ponds and standing water. Between lAilworth Castle 

 gate and Arish MU1 (Daniel) : Holwell (H. H Wood) ; Sto- 

 borough Meadows, Wareham (J.C.M.P.J, 



Genus ILPISIDIUM, C. Pfei/er. 



Closely related to the preceding genus, having its syphons 

 short and united throughout, whereas those of Sphserium are/ 

 long and separate ; the shell, too, is inequilateral 



1 . PisroiuM AMNICUM, Mutter, pL 5. 



TELLINA AMNICA, Pult. cat., Hack. ed.. p. 31, pi. vii., f. 2a. 



The largest of the Pisidia; shell subtriangular, extremely 

 inequilateral, opaque, glossy, horn-colour or yellowish-grey, with 

 concentric prominent grooves, often with a pale yellow band 

 towards the border ; furrows concentric, some deeply cut ; beaks 

 prominent, glossy ; ligament short, visible; inside nacrous white or 

 bluish. L.0.3. B.0.375. 



Hab. Slow rivers and ponds. In the watercourses of the 

 meadows near "Wareham (BrownJ, Brit. Moll., vol. ii., p. 135 ; 

 River Stour (Rackett) ; River, Chamber] ayne's, Bere Regis , 

 watercourses, West Bexington, Abbotsbury (J.C.M.P.). 



2. P. FONTINALE, Draparnaud^ pi. 5. 



Shell roundish, subtriangular, ventricose, striae concentric, well 

 denned, fine and regular, greyish-white, anterior side abruptly trun- 

 cate, posterior side rounded and sloping towards the lower margins, 

 which almost form a rectangle at their meeting ; beaks prominent 

 and rather acute ; ligament scarcely visible ; muscular and pallial 

 scars well marked as in P. amnicum. L.0.16. B.0.175. 



Var. 1. Henslowana. Each valve with a plate-like appendage 

 near the beaks. P. Henslowianum, F. and H. ii,, p. 131., pi. xxxvii., 

 f. 11. 



Var. 2. pulchetta. Shell more glossy, strongly and regularly 

 grooved ; beaks less acute. P. pule he Hum F. and H. ii., p. 128,, 

 pi. xxxvii., f. 12, 13. 



Var. 3. cinerea. Shell more broadly ovate and compressed, 

 with fainter striae. F. and H. ii., p, 125., pi. xxxvi., f. 2. 



