Fig. 2. Optic peduncle of the eyestalk in the female of Sesarma haematocheir. (A) Schematic of the longitudinal section (lateral view). t-t' represents the position of the transverse cut in part F. Scale bar, 1 mm. (B) Right eyestalk of an intact female. Scale bar, 1 mm. (C) Eyestalk after surgery. Scale bar, 1 mm. (D) Incision on the eyestalk exoskeleton before making lesions to the optic peduncle (arrow). Scale bar, 1 mm. (E) A triangle `window' was cut in the exoskeleton. `e' shows the triangle exoskeleton removed. A cluster of neurosecretory cells (nsc) is seen from the triangle window of the eyestalk. This cluster of nsc is located at the edge of the ME (see part F). Scale bar, 1 mm. (F) Transverse section (t-t' in part A). Scale bar, 200µm. (G) The right eyestalk is removed after the experiment. The dark brown triangle (arrow) shows the piece of exoskeleton returned after surgery. Scale bar, 1 mm. (H) The optic peduncle after the transverse cut of the MT (right eyestalk). A mark of the cut (C) remains. Scale bar, 1 mm. (I) Schematic detailing the optic peduncle shown in part H. Scale bar, 1 mm. (J) Optic peduncle of the female (longitudinal section: lateral view). N1 is a cluster of neurons in the MT. The region between the white lines indicates the area where the lesions were made in experiment III-4 (Table 5). Scale bar, 100µm. (K) Ventral view of the optic peduncle (right eyestalk). Black dots (N1 and N2) indicate the cluster of neurons in the MT. t-t' represents the position of the transverse cut in part L. Scale bar, 300µm. (L) Transverse section of the MT (t-t' in part K). The ventral half of the MT (under the white line) was cut in experiment III-4 (see Fig. 3). Abbreviations: ce, compound eye; nsc, cluster of neurosecretory cells; sg, sinus gland; mt, medulla terminalis; xo, X organ; mi, medulla interna; me, medulla externa; lg, lamina ganglionalis; n, cluster of neurons on the medulla interna.