XIV.—On Intestinal Respiration in Annelids; with Considerations on the Origin and Evolution of the Vascular System in that Group.

Abstract

The investigations recorded in the present paper have been carried out at various times during the last six years. A number of the observations on aquatic Oligochæta were made some time ago in India, and, along with some of the theoretical conclusions, formed Part IV. of a Thesis (“Studies on the Aquatic Oligochæta of the Punjab”) presented in 1909 for the D.Sc. degree of the London University. This division of the paper has been considerably extended as a result of further investigations on Indian freshwater forms, and on the littoral Oligochæta of the Clyde, the latter carried out at Millport in 1909. The portion of the present paper which is concerned with the Polychæta and smaller groups represents work done in 1909 at Millport, and in 1912, during my occupancy of the London University table, at the Plymouth Laboratory.