358 MARSHALL: ADDITIONS TO “ BRITISH CONCHOLOGY.” 
not half the size of those dredged off the coast in 20 f. 
It is scarce in Scotland, but somewhat diffused—Firth of 
Forth (Scott) !; Sound of Sleat, 40 f.; Loch Inver, 25 f. ; 
Barra, 20—45 f. (Somerville and J.T.M.); Kyles of Bute, 
14—25 f. (J.T.M.); Loch Linnhe, 24 f. (Knight) ! 
Both Sowerby’s and Jeffreys’ figures are good outlines ; 
but the sculpture of the latter is too obscure. In the 
former, coarse papillz are indicated as the sculpture of the 
ribs, instead of curved transverse plates, as in C. minimum, 
though coarser. The figure in “ British Mollusca” is per- 
fect. ‘The sculpture commences in the young as rounded 
tubercles or papillz, these becoming oblong as the shell 
increases, and arched as they reach the margins. Occa- 
sionally the valves are divided into two zones by a deep 
line of growth, the upper half having tubercles, and the 
lower half plates. Specimens from Glengariff are exqui- 
sitely sculptured. 
Var. ovata Jeffi—Sculptured as the type. Guernsey and 
Herm ; Torbay ; Bantry Bay; Lamlash Bay, 15 f. ; Knap- 
dale Lochs, to f. 
Var. rosea Lamk.—Channel Islands, at low water, with the 
type. 
I have an inequivalve monstrosity of the var. vosea from 
Herm ; it resembles Meger/ia in shape. 
C. edule L.—In comparison with the three preceding species, 
the very young and fry are more oval, the umbones more 
convex, and the beaks more obtuse and central. In all 
stages of growth there is a long and a short form. 
Var. rustica Chem.—A form of this variety, oval and 
equilateral, is found occasionally on our shores; it is 
the var. dalthica of Beck. 
C. minimum Phil.—S.W. Isle of Man (L.M.B.A.)!; Scilly, 
40 f., many valves; Guernsey, 20 f., a valve; west of 
J.C., vi., Apr. 1897. 
