Eu sta' chi an (eu sta' kian) tube, a passage between the pharynx and the middle ear.

Ex ha' lent, flowing or moving away from the body.

Ex' o skel' e ton, an external skeleton.

Eye stalk, an appendage which bears an eye on its free end.

Fe' mur, (1) the thigh bone; (2) the third joint of an insect's leg.

Fer ti li za' tion, the fusion of male and female elements in reproduction.

Fi' bers, flexible threads; fibers of a horny material are found in the walls of many of the sponges.

Fib' u la, the outer of the two long bones of the lower leg.

Fin, a paddle-like structure for swimming.

Fin-rays, the framework of the fins of fishes.