Catalogue entry no. 557a by Max Loehr:
557 Pair of Pigs
Mixture of light gray stone and green and yellowish jade. Similar to the preceding pair in regard to form and finish. The carved design of the heads and limbs is more strongly conventionalized than in the preceding pairs. Again, the juxtaposed side of the two pieces (a, left side; b, right side) are left uncarved. Perforations like those in the preceding three sets (Nos. 554, 555, 556). Probably Eastern Han.