parallel to the body, in order to project the fæcal refuse to the anterior extremity of the tube, he ascribes a similar structure to the present species. "In A. auricoma," he observes, the tail-like appendage to the inferior extremity of the body, in all respects but one, is formed on the model of that of the former species. One labium of the terminal orifice is here extended into a flap-like process, which, by a sudden act of muscular contraction, imparts a smart blow to the fæculent mass as it escapes from the intestine, and thus effectively conveys it to the upper outlet of the tube." (p. 208). Again, in treating of the alimentary system of the genera Serpula, Sabella and Amphitrite, he remarks that "it is through the agency of the water-current that traverses the whole interior of the body, that the fæculent refuse is projected from the bottom to the upper orifice of the tube, and that the habitation of the worm is maintained in a state of never-varying cleanliness and purity." (p. 225).
I am absolutely certain, however, that in my specimen of A. auricoma the discharge is terminal. As the animal lies on the bottom, a stream of water issues from the hinder end of the tube, not constant but intermittent, by which the adjacent sand is driven away with force, forming a furrow, a third of an inch long, extending from the end of the tube. The terminal portion of the tail itself is occasionally protruded through the aperture, and moved round with agility. When the tube with the contained animal is removed from the water and again replaced, a bubble of air escapes from the posterior orifice; and when the
