[Ultrastructural study of sinus gland regeneration in the oniscoid Porcellio dilatatus Brandt, further data on the origin of this neurohemal organ].

In this paper we analyse the consequences of cutting off axonal track connecting the neurohemal organ (sinus gland) to the pericarya of the protocerebron median part (cortical zones I' and V' - Fig. 1). After cutting the optic lobe, at the medulla interna level (cortex IV' - Fig. 1) a functional neo-sinus gland with 3 types of endings and glial cells is form again. We experimentally investigate the limits of the regeneration area of the sinus gland. Investigation of atypical but functional sinus gland (Fig. 4) allowed us, on one hand, to specify these limits and on the other hand to relate the endings of type III to a cellular type missing in the protocerebron central part. The dynamic study of the setting up of a neo-sinus gland is a quick phenomenon: exocytosis can be seen 24 to 48 h after cutting the optic lobe (Fig. 7). The optic lobe cutting off induces ephemeral modifications, on the one hand, at the level of the beta 1, neurosecretory cells: decrease of golgi activities, crinophagy, presence of crystalline-like structures; on the other hand, at the level of the nearby glial cells which show a lot of dense bodies (Fig. 9, 12).