two islands of this name in the sea lying between Britain and Ireland. The one described by Cæsar, as situated in the mid-passage between both islands, and stretching out in length from south to north. Called Monæda, (Ptolemy); Monapia, or Monabia, (Pliny). Supposed to be the Isle of Man. Another Mona, (Tacitus); an island more to the south, and of greater breadth; situate on the coast of the Ordovices, from whom it is separated by a narrow strait. The ancient seat of the Druids. Now called Anglesey, the island of the Angles or English.

an island of the Baltic-Sea, south-west of the island of Zealand, subject to Denmark. E. Long. 12° 30'. N. Lat. 55° 20'.

MONADELPHIA, (from μονάς "alone," and ἀδελφία a "brotherhood") a single brotherhood; the name of the 16th class in Linnaeus's sexual system, consisting of plants with hermaphrodite flowers; in which all the stamens, or male organs of generation, are united below into one body or cylinder, through which passes the pointal or female organ. See Botany, p. 1296.