[Stages of development and growth of the thyroid gland and adenohypophysis of the dogfish embryo (Scillium canicula Cuv.), a chondrichthyan fish].

The thyroid morphology, histology, biometry and its anatomical connections are studied during the whole embryonic life in the small spotted dogfish (Scyllium canicula Cuv.). The first differentiation of the gland appears as a thickening of the pharyngeal floor, containing PAS inclusions, at stage 10 mm. The first follicles are apparent at stage 30 mm. The thyroid volumetric relative growth is studied during the whole development and is compared with the absolute embryonic length growth. Volumetric variations of the hypophysis upper parts and ventral lobe are also studied during the whole embryonic life.