MYTILUS. MUSSEL. 115 
15. Mytilus stagnalis. Stagnant Mussel. 
Sowerby , Brit. Miscell. pi. 16. 
Shell oval, convex, of a greenish color which becomes of 
a yellowish brown towards the margin, and marked with 
darker longitudinal rays, strongly striate orsomewhat ribbed 
transversely: length live inches 3 breadth eight. 
Found in Kew garden. 
16. Mytilus dentatus. Toothed Mussel. 
Shell oval, very convex thin and fragile ; rounded and 
broader at one end, narrowed and rounded at the other, 
wkre the back is depressed, slightly angular and flexuous, 
irregularly striate trails versely, and somewhat wrinkled lon¬ 
gitudinally : color glossy sea-green, growing qlive-green or 
brown at the sides and margin, with numerous faint broken 
yellowish white longitudinal rays : beaks nearer the broader 
end, ahnost obliterated, perlaceous 3 inside silvery or fawn- 
cclor, often rough with purple perlaceous excrescences 
towards the hnge and the angular side: in one valve a 
small projecting obtuse tooth, placed at some distance from 
the beak and nearly central, and in the other a transverse 
cloven one: length three inches and a quarter j breadth six 
and a half. 
Whether this be the M. Zellensis of Gmelin, or the M. 
stagnalb of Sowerby, we are unable to determine : but in¬ 
dependently of its shape and markings, the teeth, which 
are never wanting, are sufficient characters to distinguish 
it from the two next. 
They are found, but very rarely, in the great hog of 
Allen, in Ireland, resting upon the soft mud, where they 
ire subject to little or no agitation, v. v. 
1 ?. Mytilus cygneus. Swan Mussel . 
Lister, pi. 156. f. 11— Pennant , pi. JQ—Do?iovan } pi. 55. 
liiw, Trans, viii. pi. 3 A. f. 1. 
Shell convex, oval, thin, brittle, rounded at one end, and 
regularly sloping rather into a point at the other, where it 
ii a little compressed towards the hinge, with rugged 
transverse wrinkles and protuberances, covered with an 
olive-green skin 3 inside perlaceous : hinge smalj, nearer 
on** 
