HAGECIUS.—­The most westerly member of the Vlacq group of formations.  It is situated on the S.W. of Rosenberger, and is about 50 miles in diameter.  The rampart on the E. is continuous and of the normal type, but on the opposite side is broken by a number of smaller rings.

WEST LONGITUDE 40 deg.  TO 20 deg.

CENSORINUS.—­A brilliant little crater, with very bright surroundings, in the Mare Tranquilitatis, nearly on the moon’s equator, in W. long. 32 deg. 22 min.  Another smaller but less conspicuous crater adjoins it on the W. On the Mare to the S. extends a delicate cleft which trends towards the Sabine and Ritter rill system.

CAPELLA.—­Forms with Isodorus, its companion on the E. (which it partially overlaps), a very noteworthy object.  It is about 30 miles in diameter, with finely terraced walls, broken on the S.W. by broad intrusive rill-valleys.  The rampart on the N.E. is also cut through by a magnificent valley, which extends for many miles beyond the limits of the formation.  There is a fine central mountain, on which M. Gaudibert discovered a crater, the existence of which has been subsequently verified by Professor Weinek on a Lick observatory negative.

ISODORUS.—­The rampart of this fine ring-plain, which is of about the same size as Capella, rises at a peak on the W. to a height of more than 13,000 feet above the interior, which, except a small bright crater at the foot of the E. wall and a smaller one adjoining it on the N., contains no detail.  The region between Isodorus and the equator includes many interesting objects, among them Isodorus b, an irregular formation open towards the N., and containing several craters.

BOHNENBERGER.—­A ring-plain about 22 miles in diameter, situated on the W. side of the Mare Nectaris, under the precipitous flanks of the Pyrenees, whose prominent shadows partially conceal it for many hours after sunrise.  The circular border is comparatively low, and, except on the N., continuous.  Here there is a gap, and on the W. of it an intrusive mass of rock.  From its very peculiar shadow at sunrise, the wall on the E. appears to be very irregular.  The club-shaped central mountain is of considerable size, but not conspicuous.  S. of Bohnenberger stands the very attenuated ring, Bohnenberger A. It is of about the same diameter, has a large deep crater on its N. rim, and a smaller one, distinguished with difficulty, on its S.E. rim.  On the N. of Bohnenberger there is a bright little ring-plain connected with the formation by a lofty ridge, under the E. flank of which Schmidt shows a crater-chain.  An especially fine cleft originates on the E. side of this crater, which, following an undulating course over the Mare Nectaris, terminates at Rosse, N. of Fracastorius.