Nuculanida

Nuculanida is an order of very small saltwater clams, marine bivalve molluscs in the subclass Protobranchia.

Description
These bivalves are distinguished by the presence of relatively primitive, "protobranchiate" gills. There are a row of short teeth along the hinge of the shell. The shells are often internally nacreous.

Families
Families within the order Nuculanida include:
 * Bathyspinulidae Coan & Scott, 1997
 * Lametilidae
 * Malletiidae H. and A. Adams, 1858
 * Neilonellidae S chileyko, 1989
 * Nuculanidae H. Adams & A. Adams, 1858
 * Sareptidae Stoliczka, 1871
 * Siliculidae Allen and Sanders, 1973
 * Tindariidae Verrill and Bush, 1897
 * Yoldiidae Habe, 1977
 * Praenuculidae Mcalester, 1969 (?)
 * Pristiglomidae Sanders and Allen, 1973 (?)