Pvn H,i I'UitlS

LIMOPSIS. 161
tunculina. Gray added a fifth name (Limnopsis) in
1840 ; and Herrmannsen, being apparently misled by
Agassiz, considered Limopsis as a synonym of Brown's
genus Crenella. The last two errors may be attribut-
able, however, to lapsus calami, or to a too hasty attempt
at classification. Only a very few species were until
lately known in a recent state ;
but Mr. A. Adams has
given, in
'
the Proceedings '
of the Zoological Society
for November 1862, a description of no less than nine
additional species from different parts of the world.
Many species flourished in the tertiary,
the cretaceous period.
1. Limopsis auri'ta**, Brocchi.
and others in
Area aurita, Brocchi, Conch, foss. Subap. ii. p. 485, tav. xi. f. 9.
Body cream- colour :
mantle thin and plain-edged, open in
ft ont and at both sides :
gills consisting of two pairs—the outer
pair being the larger, and overlapping the other which is folded
together, with the edges projecting outwards : foot narrow
and worm-shaped, when fully extended longer than the shell,
from the anterior
bluntly pointed at each end ; it is protruded
side ; foot-stalk or pedicle short and broad : hyssus filmy.
Shell roundish- oval, with an oblique outline, compressed,
numerous and fine
solid, opaque, rather glossy : sculpture,
longitudinal striae, which radiate from the beaks to the outer
margins, besides equally numerous but irregular concentric
ridges, some of which are larger than the rest, and all are
more or less beaded or notched by the intersection of the
striae ; at the posterior side, these markings are deeper and
stronger, and the surface is slightly granulated: colour porcelain-white
: epidermis yellowish-brown, forming in front and
at the sides a long fringe, which projects beyond the edge
of the shell : margins rounded on all sides except at the back
or hinge-area, which is sometimes straight, giving that part
the appearance of having an ear-like appendage on each side :
beaks small, sharp, and prominent, regularly incurved : hinge-
* Eared.