Pvn H,i I'UitlS

132 MYTILID^l.
water mark to 20 fathoms, on the coasts of Cornwall,
Devon, Dorset, and the Channel Isles. The collection
of Mr. George Humphreys, the well-known dealer in
shells, made in the last century, contained a single
valve labelled lc Ireland ? ; but if the locality was cor-
rectly stated, this species
has not been rediscovered
there. I am only aware of a few (ten) places where it has
been discovered in England, though it is tolerably common
at Lulworth and Guernsey. Single valves are very
abundant in the Coralline Crag at Sutton. M. Martin
has found it in the Gulf of Lyons, and Mr. M'Andrew in
the Gulf of Tunis and the Canary Isles.
Dr. Lukis informed me that some of his finest speci-
mens were taken alive in a rock-pool lying immediately
below half-tide mark on the western shore of Guernsey.
They occupied a chink in the rock a little under the
surface of the water. The transverse ridges perhaps
denote the annual growth of the shell. The fry are so
totallv dissimilar from the adult, that I was misled into
describing and figuring
Limopsis pellucida
in the '
the former under the name of
Annals and Magazine of
Natural History ' for January 1859. They
are smooth
and oval, resembling a minute Ungulina in shape ;
hinge is placed exactly
the
in the middle of the dorsal
margin ; and the arrangement of the teeth or crenula-
tions on the hinge-line further indicates the affinity of
Crenella to Nucula.
Dr. Leach admirably described this lovely and re-
markable shell in his '
Zoological Miscellany '
" Modiola Prideaux." Unfortunately
(1814) as
the termination
of the specific name is not in accordance with the rules
of zoological nomenclature, and it must therefore be re-
jected.
It is true that Capt. Brown altered the name to
Prideauxiana in his '
Illustrations of British Concho-