Tentaculita
Tentaculita is an extinct class of uncertain placement ranging from the Early Ordovician to the Middle Jurassic. They were suspension feeders with a near worldwide distribution. For a more thorough discussion, see Tentaculites.
The presence of perforate septa and "septal necks" has been used to argue for a cephalopod affinity, whereas the shell microstructure, notably the presence of punctae, points to a brachiopod relationship.
Tentaculita also includes Cornulitida and Microconchida.