Fig. 6. In situ hybridization of peJK2 to the longitudinal section of the lobster eyestalk. peJK2 hybridised to the neurosecretory regions of the eyestalk (A), as shown by the dense accumulation of silver grains in the eyestalk section whole mount. Nuclear localization of peJK2 was shown in the neurosecretory cell groups of the medulla externa and interna (A,C), the medulla terminalis (B), the X-organs of the medulla terminalis (D), and above the lamina ganglionaris, in the retina (E). LG, lamina ganglionaris; ME, medulla externa; MI, medulla interna; MT, medulla terminalis; OM ommatidia. Bars, 500 µm (A); 100 µm (B,C), 50 µm (D,E).