This genus is probably the most speciose in the Cephalopoda. Because of the great variability among species, the genus is best defined by the other two genera; that is, Sepia is the sepiid that doesn't have the major characters that define Metasepia and Sepiella.

Brief diagnosis:

• without pore at posterior end of mantle.
• with cuttlebone length approximately the same as mantle length.