CASTANETS (Fr. castagnettes, Ger. Kastagnetten, Span. castanuelas)  , instruments of percussion, introduced through the Moors by way of Spain into Europe from the East, used for marking the rhythm in dancing . Castanets, always used in pairs, one in each hand, consist of two pear or mussel-shaped bowls of hard wood, hinged together by a silk cord, the loop being passed over the thumb and first finger . The two halves are then struck against each other by the other fingers in single, double or triple beats, giving out series of hollow clicks of indefinite musical pitch . When intended for use in the orchestra the pair of castanets is mounted one at each end of a wooden stick about 8 in. long, which facilitates the playing . Castanets are also sometimes used in military bands and are then specially. constructed . The two halves are kept open by a slight spring fixed to a frame attached to the hoop of a side drum, and the instrument is worked by the drummer with an ordinary drum-stick . An instance of the use of castanets in opera occurs in the Habanera in Carmen . A quaint description of castinatts is given in Harleian MS . 2034 (f . 208) at the British Museum (before 1688) with a pencil sketch which tallies very well with the above . The MS. is by Randle Holme and forms part of the Academy of Armoury . Castanets (KpbraXa) were used by the ancient Greeks, and also by the Romans (Lat. crotalum, crotala) to accompany the dances in the Dionysiac and Bacchanalian rites .