THE STRUCTURE AND REACTIONS OF THE TENTACLES OF TEREBELLA MAGNIFICA W

¹ From the Bermuda Biological Station for Research and the Biological Laboratories, Harvard University

1. The tentacular filaments of Terebella magnifica W. are remarkably independent in their behavior after removal from the worm. Their functions are varied and they possess many features typical of an intact organism.

2. A deep ciliated groove acts as a collector and conductor of food to the body of the worm. The epidermis contains numerous specialized mucous cells.

3. The nervous system of the tentacle consists of five longitudinal bundles of nerve fibers with circular connectives or branches occurring at regular intervals.

4. Both intact and isolated tentacles are sensitive to light and in either case the reaction time over a fairly wide range of intensities is of the order of 0.5 second.

5. Local electrical stimulation elicits a response of only that portion of the tentacle proximal to the electrodes except when stimulating with rapid shocks of high intensity.

6. The experimental evidence indicates that the nervous system consists of direct receptor-effector elements which conduct primarily toward the base of the tentacle. There was no evidence which would seem to indicate the presence of a nerve plexus or net.