Pvn H,i I'UitlS

224 kelliidtE.
and the Sphariidce possess the peculiarity of their tube
or tubes being situate at the shorter and smaller side of
the shell, which may therefore be considered the posterior
end, the ligament being situate at the other end.
Philippi described the present genus
under the name
of Bornia, though not without some suspicion of its being
identical with Kellia. He remarks that he had no
means of seeing Turton's work on the British bivalves.
One character of his genus he conceives to be of very
great importance; and that is the absence of any mark
of a fold of the mantle—" sinus palliaris nullus." There
must be some mistake in this. The character exists in
Mediterranean as well as in British examples of the
typical species. Perhaps Philippi meant to say that the
pallial scar in Kellia is not sinuated as in the Veneriche
and allied families.
It may be well here to say that, in describing the right
and left valves, I have followed the rule laid down in
Dr. Gray's " Conchological Observations" (Zool. Journ.
i. p. 208), viz., "When a bivalve shell is placed on its
basal margin, with the ligament towards the observer,
the right and left valve will correspond with his own
sides." Some rule of this kind is indispensable, in
order to ensure a uniform method of description \
but it
appears of late years to have been left to the caprice of
every author.
Many species
of Kellia are known in a recent and
fossil state. During the formation of the Crag strata,
within the area which is bounded on the west by the
counties of Norfolk, Suffolk, and the adjacent comer of
Essex, several kinds flourished ;
but of these one only is
known to have survived, and still exists in the British
seas.