Pvn H,i I'UitlS

436 mactridjE.
which are bluntly crested or pointed in the middle, the an-
terior lateral being longer than the other ; in the left valve a
minute erect cardinal which fits into those of the right valve ;
lateral teeth in this valve ridge -like and obscure : inside
nacreous, minutely and irregularly striated towards the margin :
pallial scar distinct ; sinus rather long and tongue-shaped :
muscular scars slight, of an irregular shape. L. 0*4. B. 0*8.
Habitat : Sparingly distributed on all our sandy
coasts, from the Shetland to the Channel Isles, in 3-87
fathoms. Fossil in the Clyde beds and Coralline Crag
(Smith and Wood) ;
Sicilian and Calabrian tertiaries
(Philippi). It is extensively diffused both north and
south, from Iceland (Steenstrup) to the iEgean (Forbes),
at depths varying from 8 to 150 fathoms.
The animal is lively, and active by fits and starts—
now and then darting out and twisting about on all
sides its long and slender foot, as if for the purpose of
burrowing. The shell, which is of an elegant shape, is
frequently found in the stomachs of haddocks,
of the common plaice and other flat fish.
as well as
The Erycina angulosa of Bronn is probably identical
with this species.
2. S. ni'tida* Miiller.
My a nitida, Mull. Prodr. Zool. Dan. p. 245. Syndosmya intermedia.
F. &H. i. p. 319, pl.xvii. f. 9, 10, and (animal) pi. K. f. 5.
Body clear white : mantle fringed with numerous short
cilia :
tubes very long, closely annulated or marked across with
slight rings of a dusky hue, resembling those in certain species
of Tubularia ; incurrent tube cylindrical ; excurrent somewhat
longer and tapering to a fine point ; both are covered with a
few scattered papillae ; foot large and extensile.
Shell similar in many respects to that of S. prismaiica,
so as to be rather
but longer in proportion to its breadth,
oval than oblong : the surface has in front and at the sides
* Glossy.