DEVELOPMENT OF THE ACINOUS AND ACCESSORY SALIVARY GLANDS IN NUCELLA LAPILLUS: (NEOGASTROPODA: MURICOIDEA)

The acinous and accessory salivary glands in Nucella lapillusare derived from two distinctly separate sites; the acinoussalivary glands evaginate from the walls of the buccal cavity,whilst the accessory salivary glands arise as paired invaginationsof the epithelium of the ventral lip of the mouth. During thedevelopment of the oesophagus, the acinous salivary glands growposteriorly and come to lie behind the nerve ring, but are pulledanteriorly through it when the proboscis elongates during development.The ducts of the accessory salivary glands fuse to form a singleduct with paired tubular glands during proboscis formation.The secretory cells in both pairs of salivary glands differentiateprior to the crawlaway's emergence from the egg capsule. Theontogeny of the salivary glands in Nucella shows that the accessorysalivary glands cannot be homologdus with the acinous salivaryglands or venom apparatus of the Conoidea. (Received 13 September 1996; accepted 25 November 1996)