Mytiloida
Mytiloida is an infraorder of marine bivalve molluscs. This group includes many familiar bivalves such as mussels and pen shells. Mytiloidans are characterized by their elongated, equivalve shells, meaning both shells are of similar size and shape. The shells are typically inequilateral, with the umbones (the oldest part of the shell) located near the anterior end.
A prominent feature of most mytiloidans is their strong posterior foot, which is used for secreting byssus
Mytiloidans are filter feeders, drawing water into their mantle cavity and extracting organic matter and plankton
The infraorder Mytiloida is divided into several families, with the Mytilidae being the largest and most well-known.