Pvn H,i I'UitlS

LUCINA. 239
to each side. In the present species the striae run ob-
liquely from one side to the other, curling upwards at
each end. L. divaricatus is very convex, white with a
tinge of pale yellow, and rather glossy, while L. pisi-
and dull hue.
The markings on the latter shell are such as may be seen
formis is compressed, and has a rosy tinge
on the tip of a finger, and from these the names digitaria
and digitalis have been derived. It occurs in the Red and
Coralline Crag. In consequence of the anterior mus-
cular impression being simple, Searles Wood placed this
shell provisionally in Astarte ; and Deshayes has lately
formed out of this and other allied fossil species the
genus Woodia, a just compliment to our distinguished
palaeontologist.
Genus II. LUCI'NA* Bruguiere. PL V. f. 5.
Body somewhat compressed: mantle having the margin
waved : incurrent as well as excurrent tube sessile : foot tongue-
shaped.
Shell rather inequilateral, concentrically ridged: lunule
long and well denned : ligament for the most part
external :
teeth, one or two cardinals in the right, and always two in the
left valve, one of which latter is often cloven ; laterals long
and laminar : inside chalky and pit-marked.
Although this genus has been divided, it must be
borne in mind that very nearly three-fourths of a century
have elapsed since it was first instituted. The
progress of conchological discovery has been unusually
rapid during the last twenty years, owing in a great
measure to the impulse and encouragement given to the
study of the Mollusca by publications specially devoted
to it, as the ' Zeitschrift fur Malakozoologie/ f
Malako-
zoologische Blatter/ and '
* An epithet of Juno.
Journal de Conchyliologie/