expansion, from one to three lines in breadth, and of a deep blue co- lour. The under surface is completely covered with tentacula, — a marginal row of them, about half an inch in length, forms a fringe of blue, annulated at the base with white, — the remainder are smaller and more slender, one to two lines in length, white or faintly tinged with blue. In the centre is a minute, tubular, prominent orifice (the mouth), half a line in diameter, of a bluish white colour. From this, as a centre, a dark-coloured elliptico-lanceolate body, three quarters of an inch in length, extends laterally, as viewed through the transpa- rent covering ; it is lodged in the hollow of the horizontal membrano- cartilaginous base.
Glaucus hexapterygius. A figure would convey, better than a de- scription, a correct idea of the form of this singular creature, which I have somewhere seen called the "Sea Lizard." Below, the animal is furnished with a slightly developed foot, in the shape of an oval disk, not projecting beyond the margin. The lateral appendages are not quite symmetrical in the number of their divisions. The tentacula upon the head do not appear to be in any degree retractile. I ob- served it to be luminous at night, the flashes emanating from the cen- tral silvery streak upon the back. When at rest, in a vessel of sea- water, the animal lies flat upon the surface with all its arms extended, but at times, its motions render it a most grotesque object, for the whole body is very flexible, and admits of both lateral and vertical motion. The Glaucus can turn round upon its back almost in- stantaneously, by bending downwards the arms of one side, and curv- ing upwards those of the other. The digital appendages can be brought into play around a common centre, so as to grasp any object, and by this means, the animal can roll itself up into a kind of ball.
Food of the Petrel Family. — In the stomachs of individuals of the Fulmar Petrel (Procellaria glacialis), dissected by me at St. Kilda several years ago, I invariably found numbers of the horny mandibles of Lepiadae. Since then I have examined others of the family, and generally with the same result. I allude particularly to the Cape Pe- trel (Daption capensis), two species of Albatross (Diomedia exulatis and D. melanophrys), and a Puffinus from the N.E. coast of Australia. From this, it is probable that the Cuttle-fish family, which swarm in the Southern Seas, approach the surface chiefly at night, when the various oceanic birds above alluded to, are no less active than during the day, for marked individuals have been known to follow a ship for thousands of miles in her course across the trackless ocean.
