Like the statuettes, they are covered throughout with a white slip laid directly on the unglazed clay, and this is often richly coloured _in tempera_. Some of the heads have the hair covered with intersecting pink lines to imitate a net, and the figures attached to them are usually coloured in the manner of the statuettes, with blue and pink draperies. There are some, however, in which the encaustic or a similar process seems to have been employed[416]; one example, in the British Museum (D 185, shown on Plate VI.), has a Hippocamp painted on either side in white and colours outlined with black, the wings being elaborately rendered in blue, brown, yellow, and pink. The same process is employed for a large cover of a vase in the British Museum from Sicily (D 1), but the figures are now nearly obliterated. The prevailing shape of these vases is that conventionally known as the _askos_, with spherical body, over which passes a flat handle and three mouths on the top; the latter are often covered in and figures placed upon them. On the front and back of these vases _appliqué_ masks of Medusa or figures in relief are usually placed, flanked by the fore-parts of galloping horses. Others take the form of a large jug or bowl with _appliqué_ ornaments. It now remains to consider the small but interesting class of terracotta reliefs, which are nearly all of the late archaic period, dating from the beginning of the fifth century. Later reliefs are nearly all architectural in character, and have already been described, as have those which were made for the decoration of tombs and sarcophagi. But the purpose for which the reliefs were made, of which we are about to speak, is not so certain. One group appears from the character of the subjects to be votive, and they may possibly have been let into the walls of temples or shrines; but the others are mostly known to have been found in tombs. The former group are found at Athens and at Locri in Southern Italy; the latter at Melos and other sites round the Aegean Sea, being usually known as “Melian” reliefs. The character of the work of these Melian reliefs (see Plate VII.) is exceedingly delicate and refined; the subjects are mainly mythological, and include the slaying of Medusa by Perseus and of the Chimaera by Bellerophon, Helle on the ram, Peleus seizing Thetis, Eos carrying off Kephalos, and the death of Aktaeon. Three classes have been distinguished,[417] of which the peculiarly Melian type has the figures cut out, without background; in the second only the outer contours are cut round, and the third consists of rectangular plaques. Brunn[418] considers that they served a definite architectural purpose, being intended to cover a field enclosed by borders, and that the holes with which they are pierced show that they were used either for suspension or attachment. But his reasons for regarding them as an archaistic survival have not been generally accepted.