. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 590 N. MARTIN AND M. ANCTIL of the tube with the fingers, a copious amount of luminescent mucus was almost instantaneously expelled through the agitated end in all trials (Fig. 7-1). The intense and bluish luminous cloud thus produced in the surrounding water was visible to the dark-adapted eye for 2-3 min. A quick examination of the inside of the tube revealed that this forceful release was immediately accompanied by a complete reversal of the worm's orientation in the tube (Fig. 7-2), the worm now positioned in a contracte
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 590 N. MARTIN AND M. ANCTIL of the tube with the fingers, a copious amount of luminescent mucus was almost instantaneously expelled through the agitated end in all trials (Fig. 7-1). The intense and bluish luminous cloud thus produced in the surrounding water was visible to the dark-adapted eye for 2-3 min. A quick examination of the inside of the tube revealed that this forceful release was immediately accompanied by a complete reversal of the worm's orientation in the tube (Fig. 7-2), the worm now positioned in a contracted state at the other end of the tube. DISCUSSION This study conclusively establishes that except for the photogenic gland of segments 10-12 the nerve cord has an essential role in the excitation and propagation of the epithelial luminescent response ofChaetopterus. The cerebral ganglia, which are poorly developed in Chaetopterus (Martin and Anctil, 1984), may play a role in the coor- dination of luminescence propagation but are not necessary for the propagation itself. This is shown by the orderly spatial sequence of luminescence propagation following stimulation of a cerebral ganglion and the experiments on electrical stimulation of intact or sectioned nerve cord. The luminescent responses to electrical stimulation of parapods and notopods are probably mediated by the nervous system for the following reasons: (1) lumi- nescence spreads, albeit to a limited extent, as a function of the intensity of stimulation, (2) electrical stimulation of the aliform notopods, which are characterized by a much greater concentration of neurites than the parapods of the other segments (Anctil, 1979; Martin and Anctil, 1984), is the only means, short of direct nerve cord stim- ulation, by which to achieve through-conduction of luminescence excitation, and (3) a well-developed subepidermal nerve plexus is present throughout the body wall (Anctil, 1979; Martin and Anctil, 1984) and may act as the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
