MARSHALL : ADDITIONS TO ‘‘ BRITISH CONCHOLOGY.” 365 
necessary to know what are small species and what are 
merely the young of larger ones; and any one investigating 
the contents of a single dredge will feel puzzled if they are 
not conversant with the young shells of different species. 
V. exoleta L.—This species attains its maximum size in large 
sandy bays; those from rough ground are smaller and more 
solid, sometimes having the margins extra thickened. A 
dwarf from Guernsey is only half an inch in diameter, and 
an elongated monstrosity from the same island has its 
counterpart in V. /incta. 
V. lincta Pult.—The largest come from Guernsey, at extra 
low spring tides, and exceed 14 inches in length. 
V. chione L.—Teignmouth (Burkill) !; Jersey, rare ; Torbay, 
rare. A pair of valves from the latter locality are 4 inches 
by 3 inches. 
V. fasciata DaC.—Specimens living between tide-marks have 
broad and irregular flattened ribs, while dredged examples 
have strong laminated ridges. The latter form is the var. 
brongniarti of Continental writers. 
Var. radiata Jeff.—Herm, low water; Guernsey, 20f.; Scilly 
(Smart and others). 
V. verrucosa L.—Low water in the Channel Islands. 
V. ovata Penn.—Couch has recorded this species as common 
in deep water off the Cornish coast, attached to the byssus 
of Pinna. 
Var. trigona Jeff.—Tarbert, 25 f. 
My cabinet contains an inequivalve monstrosity from 
Guernsey ; whence also an abnormally elongated form, 
shaped as Astfarle compressa, is occasionally dredged in 
20 fathoms. Another form, which is compressed and 
has the posterior side more produced, occurs in the same 
district and at Loch Inver, 25 f. 
V. gallina L.—The largest come from Pendine, and measure 
