Celadon vessels of this type are discussed by Julian Thompson in the article 'Chinese Celadons', Arts of Asia, November - December 1993, pp. 60-72. It appears that jars of this type originally appeared in pairs, one bearing around its shoulder the 'green dragon of the East', the other the 'white tiger of the West'. A pair of these jars in the Percival David Foundation is illustrated by M. Medley, Illustrated Catalogue of Celadon Wares, London, 1977, pl. IV, no. 36. Medley suggests they may have been filled with aromatic oils and then placed on their respective sides of the deceased, whose head would have been to the north.
A very similar jar and cover from the Avery Brundage collection in the Asian Art Museum, San Francisco, is illustrated by M. Tregear, Song Ceramics, New York, 1982, col. pl. 286, and another from the Shanghai Museum is illustrated in Zhongguo meishu quanji; Gongyi meishu bian; Taoci, vol. 2, Shanghai, 1988, no. 204. See, also, the slightly smaller jar with winged dragon and the cover surmounted by a recumbent dog, sold in these rooms, 21 September 2000, lot 282.