The portions of the brooch, the forms of which are altered so as to adapt them better to the reception of ornament, are the head of the pin and the two terminations of the ring, where the break occurs. The two chief ways of altering the shapes of these parts are (1) by making them spherical, and (2) by expanding into a wide flat surface; the object in both cases being to increase the area available for decoration. Sometimes, also, the ring and the long end of the pin are flattened and widened for a similar purpose. As an example of a penannular brooch with bulbous terminations to the ring and head of the pin, we have one from Co. Kildare in Ireland (R.I.A. photo, B 172). The knobs are covered with a prickly ornament produced by incised lines drawn diagonally in two directions, crossing each other, giving the whole the appearance of the head of a thistle. Several brooches of this kind have been obtained from different localities in Ireland, and there was one along with the three brooches of the type with flattened and expanded ends found with the Ardagh Chalice—a hoard of objects of purely Irish types—but their ornamentation appears to be more Scandinavian than Celtic. One of the best specimens from Skaill, in Orkney, now in the Edinburgh Museum, has a pin 1 foot 3 inches long, and the bulbous ends covered with zoömorphic designs similar to those on the Manx crosses, and on an iron axe-head inlaid with silver from the Mammen How,[421] Denmark. [421] Dr. J. Anderson’s _Scotland in Pagan Times: Iron Age_, p. 97. We next come to brooches with discoidal terminations, of a date not later than the beginning of the ninth century, as the simplest example of which may be taken one from Croy, in Inverness-shire (_Scotland in Early Christian Times_, 2nd ser., p. 23). Another, found near Perth (_ibid._, p. 21), has three raised heads on each disc; whilst one from Rogart, in Sutherlandshire (_ibid._, p. 7), has four raised heads outside the circumference of the disc, so that the terminations are altered into the shape of a quatrefoil. [Illustration: DETAIL OF ORNAMENT ON THE TARA BROOCH IN THE DUBLIN MUSEUM] [Illustration: DETAIL OF ORNAMENT ON THE TARA BROOCH IN THE DUBLIN MUSEUM] Lastly, we have brooches with flat expanded ends to the ring, of which kind three specimens in the Museum of the Royal Irish Academy at Dublin are illustrated, in order to show the way of ornamenting the expansions with one, four, and five raised bosses, having zoömorphic designs on the background (R.I.A. photos, B 163 and B 164). The area of the head of the pin available for decoration is increased by making it into a cylindrical tube.