VA Preliminary light and electron microscopic findings are presented for the first time on a species of amphipod whale louse, Cyamis ceti .
Special reference is made to the paired photoreceptor structures of the head.
Whale lice are crustacean ectoparasites of large, slow moving whales. Twenty-two known species parasitize both baleen and toothed whales. The cuticle over each eye is translucent, convex, and thinner than the rest of the cranial cuticle. Each eye is compound, containing numerous ommatidia. The electron dense crystalline cones are bipartite and composed of two cells.