Pvn H,i I'UitlS

TELLINA. 377
many parts of the south of Europe, as will appear from
the following epitome of its geographical distribution :
Behring^s Straits to Kamtschatka, White Sea, and
Nova Zembla to the Black Sea (Middendorff ) ; Finland
(Nordenskiold and Nylander) to Kiel Bay (Meyer and
Mobius), at depths varying from zero to 60 fathoms;
North of France (De Gerville and others) to the coast of
Spain (Gay); Toulon (Gay) to Mogador (R. T. Lowe) and
Sicily (Scacchi and others) ; Labrador (Brit. Mus.) to
Massachusetts (Say) and north-west coast of America
(P. Carpenter)
Sicilian pliocene strata.
. It is also fossil in the Uddevalla and
This species, so familiar to modern geologists, and such
an important test for the discrimination between older
and newer or quaternary deposits, was well characterized
and figured by Lister. His method of giving the dimen-
sions of a bivalve shell is generally correct and that
which is now recognized, viz. the length representing the
line of growth in the direction of the beaks, and the
breadth the extent from side to side. Chemnitz has given,
in a vignette in the sixth volume of his (
Conchy lien-
Cabinet' (p. 76), a diagram illustrating this mode of
admeasurement. The animal has been excellently de-
scribed by Bouchard-Chantereaux, who says that some-
times the only tube exserted is the branchial one, which
the animal stretches out five or six inches in length, with
a diameter of only a line, absorbing with" an astonishing
rapidity any minute object
within its reach. It is essen-
tially a hardy mollusk, accommodating itself to all degrees
of temperature, and to every kind of water from nearly
fresh to the saltest. The typical or original form inhabits
the brackish and land-locked Baltic Sea. Loven was in-
clined to consider this a degenerate variety
of the same
species as the T. solidula of Pulteney, but for the pallial