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A Rostral Sensory Mechanism in Oikopleura dioica (Appendicularia)
Author(s) -
Bollner Tomas,
Holmberg Kaj,
Olsson Ragnar
Publication year - 1986
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1986.tb00868.x
Subject(s) - biology , sensory system , olfaction , cilium , anatomy , sense organ , olfactory bulb , olfactory system , vertebrate , neuroscience , microbiology and biotechnology , central nervous system , genetics , gene
The ventral sense organ, below the mouth, is composed of 30 primary sensory cells situated in a row perpendicular to the long axis of the animal. Each cell carries one long and slender, modified cilium which arises from an apical pocket in the cell. The sensory cells project 15 axons at each side of the pharynx to the brain, which is rostrally paired and terminates in bulb‐like swellings. Each of these bulbs contains four cell bodies, which, according to their fine structure, as well as the synaptic connections with receptor and brain fibers, belong to three different types. It is suggested that the sense organ is a chemosensor and that its remarkable similarity to the vertebrate mechanisms for olfaction makes it probable that the appendicularian Oikopleura dioica possesses a ‘protochordate’ counterpart to the craniate olfactory apparatus.