THE MOVEMENT AND REGULATION OF CILIA ON THE PARAPODIA OF NEPHTHYS BUCERA, EHLERS

¹ From the Department of Biology, Brooklyn College, and the Marine Biological Laboratory, Woods Hole, Mass.

1. The cilia of Nephthys are grouped into small tufts on the branchia and on the body wall of each parapodium. Each tuft is limited to a single cell and consists of 40 to 50 large compound cilia. Each compound cilium is made up of smaller units.

2. The longest cilia measured were 62 µ while the shortest ones were 5.6 µ.

3. The cilia of Nephthys in their effective and recovery strokes move according to the flexural type.

4. The corresponding cilia of each tuft along the branchia move synchronously while those exactly across the branchia are opposite in their phases of movement.

5. The effective stroke of the cilia is at right angles to the metachronal wave.

6. Iron hematoxylin, with or without a counter stain, showed intracellular fibrils passing from the base of each ciliated cell to the cilia. This stain showed also many fibers within the basal membrane beneath the ciliated cells. There was no connection between the fibers within the basal membrane and the intracellular fibrils of the ciliated cells.

7. Both Vom Rath's stain and methylene blue showed the cytoplasm of the ciliated cells to be granular.

8. Physiological tests indicate each ciliated cell to be independent and that it regulates its own activity.

9. Stains and the results of physiological experiments indicate the ciliary system of Nephthys to be independent of the nervous system. Possibly a neuroid mechanism is responsible for the ciliary coördination of these cells when they are in their natural location.