ABSTRACT
Pedicellariae of Schizaster canaliferus (Echinoidea, Spatangoida) were examined using light, transmission, and scanning electron microscopy. Special emphasis was given to the venom apparatus of globiferous pedicellariae. Dentate pedicellariae were represented by tridentate, in small, medium sized, and large forms, as well as quadrodentate ones. Tridentates were common all over the test, quadrodentate and rostrate pedicellariae were aggregated around the peristome. The long stalked globiferous pedicellariae occured in low abundance in 4 ambulacra, the short stalked form reached high densities only around the periproct. Globiferous pedicellariae have 3 jaws, which are provided with a venom apparatus lying within the calcareous valve. The venom apparatus consists of a venom gland, a secretory duct, and 8–10 pointed teeth. Release of venom in echinoids is typically due to the contraction of a sheath of muscles, situated on the outer side of the venom gland, in S. canaliferus no muscles around the venom glands were detected. Venom release is supposed to be induced by a swelling process. The structure of the globiferous pedicellariae of S. canaliferus is very similar to Cidaroidea.
