ABSTRACT
Globiferous pedicellariae are defensive, glandular tri-jawed appendages located on the outer body surface of most echinoids. Each jaw is provided with a venom-apparatus and is supported by a calcareous valve. The morphology and fine structure of globiferous pedicellariae in Sphaerechinus granularis were studied using light and electron microscopy, with special attention being given to the venom apparatus. The secretory duct extends to the apical lobes and surrounds the terminal tooth. The duct-lining epithelium consequently lies partly on the tooth itself (i.e. the epithelium of the inner side of the duct) and partly on the pedicellarial dermal tissue (i.e. the epithelium of the outer side of the duct). Cells of the duct’s outer epithelium have conspicuous fibrillae (presumably myo-fibrillae) running all along the cell length. Release of venom by globiferous pedicellariae results from different mechanisms that presumably act together. Injection of the venom is basically due to the contraction of the muscle sheath surrounding the venom gland.
