Fig. 1. Preparation. (A) The isolated apposition compound eye was mounted on a plastic rod with the aid of low melting point bee's wax/dental wax and placed into a glass bubble filled with saline so that the mid-band was oriented horizontally. The intracellular electrode was lowered through a small hole cut into the cornea of the dorsal (or ventral) hemisphere. (B) Frontal view of a left eye of Gonodactylus chiragra mounted as in A. The eye is divided into a dorsal and a ventral hemisphere by an equatorial mid-band formed by six rows of enlarged ommatidia. The mid-band rows are numbered 1 to 6 from dorsal to ventral. Ommatidia in rows 1-4 belong to type II, whereas ommatidia in rows 5 and 6 belong to type I (see Fig. 2). D, dorsal; V, ventral; L, lateral; M, medial. Scale bar, 1 mm.