Copepod a

Entomostraca, with a shell, not formed by the folding back or down of the skin, and with biramous swimming appendages on the thorax, but none on the abdomen; e.д., Су clops. Many Copepods are morphologically degraded through parasitism, such as Actheres and various Fish-lice. There are two sub-orders, Eucopepoda and Branchiura.