Gold ornaments for the arms, known by the term _armillæ_, are sometimes of the same thickness throughout. It is more usual to find them plain, though twisted work was also applied to them. The majority have dilated ends, or ends slightly concave. With others, again, these cavities assume the form of a cup so expanded as to present the appearance of a trumpet or the calyx of a large flower. On ornaments somewhat resembling the latter the dilated extremities are flat plates, while the connecting part, diminutive in proportion to their exaggerated size, is striated longitudinally. These objects are usually described as dress-fasteners, but the exact purpose for which they were employed is still a matter of doubt. Advanced skill in the art of enamelling is one of the most notable features of the Late Celtic period, which itself extended from the prehistoric Age of Iron and over the period of the Roman occupation. This enamel, executed by the champlevé process on copper and bronze, served for the decoration of massive bronze penannular bracelets, and for bronze pins with wheel-shaped heads. In addition to brooches--all of the safety-pin type--of an immense variety of design, other primitive bronze ornaments, usually of the spiral form characteristic of Celtic work, include torques, armlets, and anklets. The torques are mostly penannular and have enlarged terminals; the armlets are often complete rings. For the most extensive representation of the prehistoric gold ornaments of the British Isles one must look, not to England whose inhabitants generally assumed the types of ornament in use among their Roman conquerors, but to Ireland, where the Celtic traditions were continued, and which has revealed vast hoards of golden treasure. In Celtic England during the Bronze and Early Iron Ages the majority of personal ornaments are of bronze; in Ireland, however, at the same periods the greater number are of gold. The objects belonging to the Royal Irish Academy in the Dublin Museum--perhaps the largest collection in Europe of prehistoric gold ornaments--represent merely a fraction of what, during the last few hundred years, has been discovered and consigned to the crucible. Usually described as head-ornaments are certain crescent or moon-shaped plates of thin gold, generally decorated with engraved designs in parallel lines, with angular lines between them, and having their extremities formed into small flat circular discs. These gold _lunettes_ or _lunulæ_ are considered to have been worn upright on the head and held in position by the terminal plates set behind the ears,[7] but they were very probably worn round the neck. The finest at Dublin is of pure gold, weighing upwards of sixteen ounces, and is richly ornamented with rows of conical studs. [7] Wilde (W. R.), _Cat. of antiquities of gold_, p. 12.