WikipediaRead full entry The shells are long, narrow, and
parallel-sided. This shape resembles a closed, old-fashioned
straight razor (a cut-throat razor), or a closed jackknife
(pocket knife) and sometimes these clams are known as razor
shells or jackknives. The shells in these species are fragile
and can easily be damaged when digging for these clams. Ensis
species live in clean sand on exposed beaches. They are capable
of digging very rapidly; see the description under the Atlantic
jackknife clam. Some clammers catch jackknives by pouring salt
on the characteristic keyhole-shaped breathing holes. The clam
then tries to escape the salt by coming up out of its hole, and
at this point it is possible to gently grab the shell and pull
it out of the ground. Thirteen species are currently recognised:
- Ensis arcuatus (Jeffreys, 1865) – razor shell - Ensis
californicus Dall, 1899 - Ensis directus (Conrad, 1843) –
Atlantic jackknife clam - Ensis ensis (Linnaeus, 1758) - Ensis
goreensis (Clessin, 1888) - Ensis macha