MYA. GAPER. 
104 
16. Mya dubia. Doubtful Gaper. 
Pennant , pi. 47— Donovan , pi. 108— JFood, pi. 25. f. 2 
3— Dorset Cat. pi. 1. f. 11. 
Shell oval, thin, brittle, opake, light brown, white 
within, irregularly wrinkled or ragged transversely, with a 
very large open gape in front, commencing near the hinge, 
becoming narrower towards the smaller end, and exposing 
the interior of the hinge and the rudiments of teeth: beaks 
small, prominent, placed at the larger end : hinge with a 
small plate or rudiment of a tooth in both valves, projecting 
inwards : length not half an inch 5 breadth about three 
quarters. 
Imbedded in the hardest rocks, v. v. 
17. Mya arctica. Arctic Gaper. 
Shell oblong-oval, rather convex, coarse, greyish-white, 
truncate at the hinge end, and something rounded at the 
other, where it gapes a little, roughly striate transversely, 
with the strife approaching to membranaceous ridges to¬ 
wards the hack, a little inflected on the front margin: beaks 
prominenc, pointed, close to the truncated end, from which 
run two raised ridges, one along the back margin, the other 
obliquely to the outer angle of the front margin, both of 
which are rough or somewhat spinous by the sharp dupli- 
cature of the transverse folds ; under the beaks also, on 
the truncated slope, is an oblong striate depression j inside 
glossy white, with the margin plain : hinge with a strong 
projecting spoon-shaped cavity in each valve, the edge of 
which next the flattened side is a little raised so as to re¬ 
semble a small tooth ; from this cavity along the cartilage 
margin, runs a small hollow groove in each valve, and be¬ 
low the hinge on the truncated margin withinside is a flat- 
tened space in both valves, in the middle of which thereis 
an oblong cavity : length half an inch 5 breadth more than 
three quarters. 
A living specimen of this very desirable shell we took 
from a m iss of Sertularia, on the strand at Portuiarnock, 
in Dublin hay. It had for some time been undistinguished 
in our cabinet, among a parcel of the Solen minutus; and 
it is probable that it may in this manner have been over¬ 
looked by other collectors. 
Fabricius, 
