Pvn H,i I'UitlS

232 lucixid^.
Genus I. LO'RIPES * Poli. PL V. f. 4.
Body somewhat compressed : mantle having the margin
notched : incurrent tube rather long and wrinkled : excurrent
tube sessile : foot awl-shaped.
Shell almost equilateral, irregularly cancellated, or sculp-
rather the
tured by nexuous striae : lunule short : ligament (or
cartilage) quite internal : teeth, one cardinal in the right, and
two in the left valve ; laterals remote and sometimes indistinct.
The celebrated Neapolitan eonchologist, Poli,, who
founded this genus, described the shell under another
name— that of Loripoderma — a hybrid compound, or
" Babylonish dialect/' which fortunately we are not
obliged to use. It may be known from Lucina by the
different position of the ligament or cartilage, which is
external in that and internal in this genus. Deshayes
is of opinion that the structure of the ligament is of
more consequence than its position; but the structure
or composition of every kind of ligament or cartilage is
the same, and it appears to me that the position of this
apparatus deserves to be considered in any
classification. Any one character,
scheme of
if certain and not
liable to vary in the same genus, is as good as another
for this purpose.
Searles Wood says that " this is a recent genus, and
its age, as far as it is known to me, does not extend
bevond the middle tertiaries." It is difficult to distin-
guish the genus Ungulina of Daudin from Loripes. Ac-
cording to Chenu, the ligament in Ungulina is external ;
but its exact position is in a groove on the hinge-plate,
within the dorsal margin.
* So named from the thong-shaped foot.