The anatomical term heterodont (from Greek, meaning 'different teeth') refers to animals which possess more than a single tooth morphology. For example, members of the Synapsida generally possess incisors, canines ('eyeteeth'), premolars, and molars. The presence of heterodont dentition is evidence of some degree of feeding/hunting specialization in a species. The term heterodont can also refer to members of the Subclass Heterodonta of the Class Bivalvia. The name refers to the differentiated hinge teeth which hold together the valves of the shell.