Shell very large up to 520 mm in length, ventricose, ovate or globose, thick or very thick, sharp or slightly sharp shoulder crest. Juvenile shells usually more elongate becoming globose in adult. Protoconch situated above or sometimes below shoulder of last whorl, in juvenile protoconch protrudes above shoulder of last whorl. Sub-adult to adult shells usually have no spines in about last half of last whorl. Early growth of spines from half to three quarters of first whorl, spines terminating on adult shells up to a quarter or up to seven eighths of last whorl. Teleoconch of 3-3,25 whorls. Shoulder with a row of long and slender, almost straight or slightly curved spines, rather spaced at a separation of 7-11 per whorl, length 7-24 mm. Protoconch dome-shaped, of 2,5-3,5 whorls, light brown or cream, finely spirally striated, radial striae fine becoming coarser towards suture, diameter 10.2-11.0 mm, height 5.2-5.6 mm. Radial growth striae rather coarse, crossed with fine spiral striae. Ground colour pale cream or straw colour with two spiral brown bands or spots which intersect with wide radial streaks or zigzag lines; colour occasionally either solid brown or marbled with white. Aperture wide, ovate or semi-circular, posterior outer lip relatively flat. Internally cream, light cream or pale orange, sometimes orange near outer lip. Parietal wall and inside aperture glossy. Columella arched, with three strong oblique plaits. Siphonal canal notch wide and deep, fasciole well defined. Periostracum thin, light brown.

The shell shape of M. amphora is very variable, some being elongated and some globose, sharp or slightly sharp shoulder crest. Growth of spines on M. amphora usually ceases early while growth or round rotation is still in progress, usually until quarter of the last whorl, in some cases even seven eighths of the last whorl. Juvenile shells are elongated, while the adult form becomes more globular. Sometimes M amphora can be confused with Melo umbilicatus (see the discussion in M. umbilicatus for further clarification). Juvenile to adult shells of M. amphora from Warialau Island, Aru Islands, Maluku are generally slightly elongated in shape and with a dominant radial brown colour or with white marbled pattern. Melo amphora shells can also be found with a prominent spire, and some shells from the Aru Islands, Maluku have a very thick shell, up to 10 mm. Compared to M. aethiopicus which is usually globose in shape, the posterior outer lip is extended upwards, and has short and numerous spines (12-18). Melo georginae (Gray in Griffith & Pidgeon, 1834) from southern Queensland, Australia has spines that reach to the outer lip, whereas in sub-adult or adult shells of M. amphora usually the spines do not reach the outer lip. Melo amphora knighti Jackson, 1954 from Queensland, Australia, was described based on the albinism mark or white colour inside the aperture (Jackson, 1954, p. 35-37, pi. 2, fig. 1). White internal shell aperture can be found in several of Melo species, such as Melo umbilicatus, M. amphora and M. aethiopicus, they live on white sand and clear water area.

Distribution. In Indonesia, M. amphora originates from the islands of the Aru Islands in the Arafura Sea, Maluku. The distribution of M. amphora outside Indonesia follows Hinton (1977), Bail (1990), Poppe & Goto (1992) and Morrison & Wells (2005) .
Habitat. On muddy sand from shallow water to a depth of 80 m. Taken by fishermen diving to a depth of 45 m and from trawling at greater depths.