Pvn H,i I'UitlS

AxiNtrs. 245
Palissy's workmanship impose on a palaeontologist of any
experience. The shell of L. borealis has a considerable
tendency to vary in respect of the remoteness or proximity
of the striae. In some Guernsey specimens the ribs
nearly disappear towards the front. A specimen from
Exmouth has a minute pearl lodged between the pallial
impression and the inner margin. The young are ob-
liquely triangular, and marked with a few irregular
white streaks which radiate from the beaks. The frv are
almost globular, perfectly smooth, and glossy. Specimens
of an extraordinary size are got at Tenby. My son
picked up a single valve on the sands there, measuring
two inches in breadth and nearly as much in length.
Petiver first noticed this species as British, and called
it the " thread- girdled white Cockle." Donovan recognized
it as the Venus borealis of Linne. It is also the
V. spuria of Gmelin (from the figures of Lister and
Chemnitz), Tellina radula of Montagu,
and Venus cir-
cinnata of Brocchi. The type of Turton's Lucina alba
is composed of two odd and much-worn valves of
L. borealis. The L. lactea and L. leucoma of Macgilli-
vray also belong to the present species.
Genus III. AXI'NUS * J. Sowerby. PL V. f. 6.
Body convex : mantle having the margin thickened, with-
out tubes :
gills two on each side, an outer and inner pair :
foot nearly cylindrical and very slender.
Shell globular, with somewhat of a triangular outline,
smooth ; posterior side longitudinally furrowed, or angulated :
heaks much recurved : lunule short and sometimes indistinct :
ligament usually and to a certain extent external, placed
in a
groove or excavation on the hinge-line, and outside the hingeplate
: teeth altogether wanting.
* Hati-het-shaped.