closely watched the flight of this wonderful bird know, is ever in motion, sometimes flapping on the surface of the sea as it dips to a wave, or elevated as it turns in the force of the gale, and, though no doubt difficult to observe, it is in constant quiver of slight rotation of the broad plumes, opening and closing like Venetian blinds. We have in the mechanism thus described a sufficient source to sustain the prolonged, and to the casual observer apparently effortless, flight of the albatros. The locking of the elbow-joint in the albatros is exactly analogous to the locking of the knee-joint of the human skeleton by which man maintains without fatigue that erect attitude which proclaims his supremacy. It is very much to the point that the only other bird which posseses a patelloid bone controlling the elbow-joint as the patella does the knee-joint is the penguin, and in this case the wing-bones have also to be kept rigid during the penguin's flight under the water.

Art. XXXIV.—Further Contribution to a Knowledge of the New Zealand Sponges. By H. B. Kirk, M.A. [Read before the Wellington Philosophical Society, 28th November, 1894.]. Plates XXIV.–XXVI. In my former paper on New Zealand sponges I expressed an intention of describing the New Zealand sponges in something like their natural order. I think it best, however, to describe at once the two very interesting sponges that form the subject of this paper. I also abandon the intention of copying, except in rare instances, the descriptions, of New Zealand sponges already published. Sycon dendyi, n. sp. Plate XXIV. The genus Sycon is thus defined in Dr. Dendy's “Synopsis of the Australian Calcafea Heteroccela”: Sycettidæ with “radial chambers not inter-communicating; articulate tubar skeleton; the distal ends of the chambers provided each with a tuft of oxeote spicules.” The definition above given, taken with that of the family Sycettidæ, did not contemplate the inclusion of such a sponge as forms the subject of this paper—a sponge that has a well-developed cortical skeleton of large oxea, through which the