confluence of the lava issuing from which would naturally yield the appearance of one streak of great width. Some of those diverging from Tycho are of this class; many other examples might be cited, among which we may name the wide streaks proceeding from the crater Menelaus and also those from Proclus. Some of these occupy widths upwards of 25 miles—amply sufficient to admit of many concurrent cracks with confluent lava outflows. We are disposed to consider as related to the fore-mentioned radiating streaks, the numerous, we may say the multitudinous, long and narrow chasms that have been sometimes called “canals” or “rills,” but which are so obviously _cracks_ or chasms, that it is desirable that this name should be applied to them rather than one which may mislead by implying an aqueous theory of formation. These cracks, singly and in groups, are found in great numbers in many parts of the moon’s surface. As a few of the more conspicuous examples which our plates exhibit we may refer to the remarkable group west of Treisnecker (Plate XI.), the principal members of which converge to or cross at a small crater, and thus point to a continuity of causation therewith analogous to the evident relation between the bright streaks and their focal craters. Less remarkable, but no less interesting, are those individual examples that appear in the region north of (below) the Apennines (Plate IX.), and some of which by their parallelism of direction with the mountain-chain appear to point to a causative relation also. There is one long specimen, and several shorter in the immediate neighbourhood of Mercator and Campanus (Plate XV.); and another curious system of them, presenting suggestive contortions, occurs in connection with the mountains Aristarchus and Herodotus (Plate XVIII.). Others, again, appear to be identified with the radial excrescences about Copernicus (Plate VIII.). Capuanus, Agrippa, and Gassendi, among other craters, have more or less notable cracks in their vicinities.