MARSHALL : ADDITIONS TO “ BRITISH CONCHOLOGY.” 341 
P. maximus L.—The very young are occasionally found 
under stones at low-water mark in the Channel Islands, 
attached by a byssus. Up to a quarter-inch in diameter 
the upper valve is flat, after which it becomes concave, then 
gradually flat again, afterwards growing convex as it attains 
maturity. The ribs begin to appear when the shell is a 
third of an inch in diameter. 
Lima subauriculata Mont.—Some specimens approximate 
in width and length to Z. e/Ziptica of the same size, and the 
sculpture of both is variable. The longitudinal central 
groove is not always outwardly visible in either species, but 
is plainly visible inside. 
Jeffreys’ figures of both species are good, but he has 
given the extreme sizes. Southern and Irish specimens of 
L. subauriculata do not often exceed a line in length. 
Sowerby’s figure of Z. swbauriculata has been taken from 
L. elliptica, and his supplementary figure of the latter is 
L. subauriculata. 
L. hians Gm.—“ Hastings, a single valve of a young shell, 
attached to the roots of Aztennularia,” (J. of Conch., 
vol. I, p. 90); most probably a stray, or from a northern 
trawl-boat. Mulroy Bay, Donegal (Darbishire). 
Var. tenera Turt.——Scilly (Smart and others) ; Teignmouth, 
a valve cast ashore in a storm. 
Avicula hirundo L.—Off Minehead, Ireland, fragments from 
trawlers, and S.W. Ireland, 50—60 f. (Wotton); St. 
Michael’s Bay, Cornwall. 
Mytilus edulis L.—I have an inequivalve monstrosity taken 
from a fishmonger’s slab, in which one valve is flat and only 
half the size of the other. Jeffreys records a similar form 
of JZ. barbatus from the Loscombe collection. 
M. modiolus L.—Low water to 120 f. Loch Don, Mull, 
t10 f. (Coulson) ; Oban, 120 f. (Somerville) ! 
Var. umbilicata Penn.—Tenby (Span)! 
