KHODABANDEH, S.; KUTNIK, M.; CHARMANTIER-DAURES, M.*; CHARMANTIER, G.; Univ. Montpellier II, France; Univ. Montpellier II, France; Univ. Montpellier II, France; Univ. Montpellier II, France: Ontogeny of the antennal glands in the crayfish, Astacus leptodactylus.

Crayfishes owe their ability to live in freshwater to several ontogenetical morpho-functional adaptations. The results reported here, oriented toward the study of the ontogeny of the excretory antennal glands, are part of a program dealing with the ontogeny of osmoregulation in Astacus leptodactylus. The development of antennal glands starts early during the embryonic development. The tubule was observed at the metanauplius stage EI (eye index) 190 �m, the labyrinth and coelomosac at EI 320 �m, the bladder at EI 410 �m. All parts of the glands are present before hatching at EI 440 �m. An ultrastructural study was conducted in embryos (EI 350, 410, 440 �m), juveniles II and adults. The cytoplasm of coelomosac cells contains numerous vesicles and vacuoles of various sizes. The labyrinth cells present apical microvilli, the aspect of which is different according to the stage. The epithelial cells of the tubule region are smaller and devoid of apical microvilli. Starting at EI 350 �m, they present basal infoldings associated with elongated mitochondria, and numerous vacuoles. The enzyme Na /K-ATPase was found through immunocytochemistry in the distal tubule at EI 220 �m, in the proximal tubule at EI 385 �m, then in the bladder at EI 410 �m. The development of the antennal glands before hatching, along with that of functional branchial chambers, are major adaptations which allow crayfishes to spend their entire life cycle in freshwater.