388 MARSHALL: ADDITIONS TO “ BRITISH CONCHOLOGY.” 
inner case or double shell on the posterior side,” is by no 
means rare; I have several similar examples. Some large 
valves of Z. oblonga from Falmouth are 5 in. by 25 in. The 
young of this and the last are snow white, with a pale 
silky epidermis which gradually darkens towards the adult 
stage, aged specimens becoming almost black. 
Scrobicularia nitida Mull. — Scilly Islands (Smart and 
others) ; Cawsand Bay, Plymouth; Torbay; Aberdeen- 
shire. 
S. alba var. curta Jeff.—Jersey ; Torbay ; Skegness. 
Var. oblonga Marsh. (J. of C., vol. vii, p. 247).—Scilly 
Islands ; Milford Haven ; Bantry Bay; Arran, 3of. 
A yariable shell, both in shape and size. The Rey. 
Frank Knight has dredged some very large valves at Arro- 
char, at the head of Loch Long, measuring rg in. by ? in. 
At this place there is a considerable admixture of fresh 
water from the surrounding mountains, which would seem 
to agree with this species. A dwarf form does not exceed 
4in, in width. 
S. piperata Bell—Scilly, rare (Smart and others); Herm 
Island, very rare. 
Solecurtus scopula Turton.—Scilly (Tregelles and others). 
Solen pellucidus Penn. 
amcad| asl VU) 
S. ensis L.—Low-water mark, Jersey and Herm. 
Low-water mark, Jersey (Duprey 
S. siliqua var. arcuata Jeff_—Found sparingly with the type, 
although in some localities it is the normal form. 
Their mode of living is well exemplified by the manner 
in which an inch or two of their shells are frequently cut 
off by the dredge. In Devonshire they are caught at low 
water by dropping an iron rod down their burrows, on 
which the valves close and they are drawn to the surface. 
A pinch of salt, or a hot sunny day, brings them to the 
surface. My largest, from Sutherlandshire, is 8? in. by 
14 in., but Mr, Robertson has taken them ro} in. in 
J.C., viii., July 1897. 
