Lamp Shell Terebratulina septentrionalis It would be easy to
mistake a lamp shell for a small bivalve mollusk, as both have a
hinged shell in two parts and live attached to the sea floor.
Lamp shells, however, have a very thin, light shell and the two
parts are different sizes, with the smaller one fitting into the
larger. The shell valves cover the dorsal and ventral surfaces
of the animal whereas in bivalve mollusks they are on the left
and right side of the body. Lamp shells attach their pear-shaped
shell to hard surfaces by means of a fleshy stalk that emerges
from a hole in the ventral shell valve. With the shell valves
gaping open, the animal draws in a current of water that brings
plankton with it. Taking up most of the space inside the shell
is a feeding structure called the lophophore, which consists of
two lateral lobes and a central coiled lobe covered in long
ciliated tentacles. The beating of the cilia creates the water
current. Lamp shells are found worldwide, but they are
especially abundant in