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NATICIDAE 189
Genus Lunatia Gray 1847
Lunatia beros Say Common Northern Moon-shell
Gulf of St. Lawrence to off North Carolina.
Figure 22a
2 to 4% inches in length, not so wide; globular in shape; umbilicus deep,
round, not very large, and only slightly covered over by a thickening of the
columellar wall. Color dirty-white to brownish gray. Aperture glossy, whit-
ish or with tan or purplish brown stains. Periostracum thin, hght yellow-
brown. Operculum corneous, light-brown and thin. A very common inter-
tidal species in the New England area. The t^^ case is a wide, circular ribbon
of sand, about the thickness of an orange peel and easily bent when damp.
The tiny eggs are embedded in the ribbon.
Lunatia triseriata Say Spotted Northern Moon-shell
Plate 22m
Gulf of St. Lawrence to North Carolina.
^ inch in length, similar to young heros but the last whorl usually has
three spiral rows of 12 to 14 bluish or reddish brown, squarish spots. The
borders of the egg case are crenulated in contrast to the smooth borders of
that in heros. This is a moderately deep-water species. Not uncommon from
I to 63 fathoms.
Lunatia groenlandica Moller Greenland Moon-shell
Arctic Seas to off New Jersey.
Plate 22k
% to I inch in length, 4 to 5 well-rounded whorls. Spire about ^ the
total length of the shell. Umbilicus very small, mostly covered over by the
callus-like swelling of the top of the columella. Suture fine, deeply indented,
bordered below by a weakly raised spiral swelling. Shell white, covered by
a thin, smooth, greenish-yellow periostracum. Operculum chitinous, trans-
lucent, light-tan, paucispiral. Moderately common offshore.
Lunatia leivisi Gould Lewis' Moon-shell
British Columbia to Lower California.
Plate 2411
3 to 5 inches in length, moderately heavy. Whorls globose, slightly
shouldered a little distance below the suture. Umbilicus deep, round and
narrow. Characterized by the brown-stained, rather small, button-like callus
partially obscuring the top edge of the umbilicus. A very common species
found in shallow water to 25 fathoms. They are more commonly found in
the summer months. Do not confuse with P. draconis.