Quarterly Journal of Microscopical Science, Vol s3-89, 47-51, Copyright © 1948 by Company of Biologists

Transport of Food Through the Alimentary Camals of Aquatic Annelids

¹ Department of Zoology, Bedford college, University of London

1. In most serpulids and sabellids the only muscle coat in the wall of the alimentary canal lies outside the blood sinus which envelops it. In a few sabellids there is another muscle coat, of unknown function, between the sinus and the gut epithelium.

2. The muscles outside the sinus contract antiperistaltically and tend to hinder the transport of the gut contents towards the anus.

3. The contents of the alimentary canal are transported by its cilia which beat towards the anus. The metachronal waves of the ciliated epithelium travel in a postero-anterior direction. The ‘ascending ciliary current’ of Stephenson (1913) does not exist.

4. The food boli of serpulids and sabellids rotate as they move down the gut. In Salmacina incrustans the rotation is imparted by cilia in the anterior part of the gut.

These observations were made in the Zoological Station of Naples. I wish to record my gratitude to the staff of the Station, to the British Association for the Advancement of Science for the use of its Table, and to the University of London for a grant towards travelling expenses.