10 
ARCA. ARK, 
brown color, becoming white by exposure to the air: beaks 1 
nearly central, incurved, rather remote, with the interme¬ 
diate space rhombic black and finely but regularly striate 
longitudinally 5 inside white, entire at the margin, with 
about twenty teeth each side the beak placed in:a straight 
line : length nearly an inch; breadth something more. 
However averse we may be to the alteration of establish¬ 
ed specific names, the uncertainty in which this shell ha 
hitherto stood, and the discovery of its peculiar habitat and 
history, will we trust hold us justified in this instance. The 
Linnean Area lactea is described as having the margin 
toothed, a circumstance which has never been found subject 
to variation in any shell; nor on the contrary has any shell 
with the margin usually plain been found toothed: 3 d 
from A. barbata and A. reticulata it differs, in having the 
points of the beaks remote from each other. 
In the summer of IS 17> a large mass'of very hard cab. 
reous sandstone, dredged up in Teignmouth harbour, was 
brought to us, perforated all over the surface, and filled 
with these shells only, so compactly imbedded that it to 
necessary to break the stone in order to extricate then, 
mostly in a living state; since which they have beenfoud 
inclosed in rocks about Teignmouth and Dawlish, firmly 
attached at the front margin by a strong broad deep green 
•film; and within some of them were found the Tellina sub* 
orbicularis. This singular habitat may account for the ob¬ 
scurity in which this specie^ has remained, its rarity in t 
living state, and the variations in its figure ; being some¬ 
times angular, sometimes rounded at both ends, often a lit¬ 
tle elongated on one side, sometimes fiat, and sometimes 
very deep and as it were truncated at the front margin: 
length half an inch ; breadth nearly an inch, v. v. 
S. Area fusca. Brown Ark . 
Lister, pi. 367- f- 207— Donovan , pi. loS. f. 3, 4. 
Area Nose. Montagu , pi. 4. f. 3. 
Shell purplish-brown, elongated on one side, finely reti¬ 
culate, much resembling Area Nose, but is longer in pro¬ 
portion to the breadth, and the longitudinal striae are much 
finer, except between the angles of the longer end; and the 
upper angle of this end is considerably shorter than the 
lower 
