Description. Shell large, up to 407.5 mm in length, ventricose, ovate or globose, thin or rather thick to thick; sharp or slightly sharp shoulder crest, adult shells not usually having spines on last part of body whorl and occasionally lacking for more than half of last whorl. Protoconch position is usually above, or occasionally below shoulder of last whorl. Teleoconch of 2,25-3,25 whorls, whorl shoulders ornamented with a row of spines, short and broad at base, rather curved, rather closely spaced, 7-12 per whorl, height 6-16 mm; early growth of spines from half to three quarters of first whorl, spines terminating in adult shells from quarter to half of last whorl. Protoconch dome-shaped, of 3-3,5 whorls, light brown or cream, diameter 12-13.7 mm, height 4.3-6.8 mm, finely spirally sculptured, radial striae fine, becoming rather coarse below suture. Radial growth striae rather coarse, crossed with fine spiral striae. Colour light brown, whitish or chestnut with either two spiral brown
bands, two rows of spiral dark brown spots, a zigzag pattern, or occasionally a white marbled pattern. Aperture wide, ovate or semi-circular, slightly wider at bottom, posterior outer lip relatively flat. Aperture pale orange or cream internally, becoming more orange near outer lip. Parietal wall and inside aperture glossy. Columella arched, with three strong oblique plaits, orange in colour. Siphonal canal notch wide and deep, fasciole well defined. Periostracum thin, light brown or brown.
Type material. Puger, south of East Java, Indian Ocean: Holotype MZB Gst. 12153, 283.3 mm; Paratype SMF 366404, 218.3 mm. Lampon, East Java.

n. sp. varies. One morph is ovoid and rather thick, the other is globose and thin; both types can be found from the same locality, or usually one type is dominant in that locality. The globose, thin shells are found in Banyuwangi, East Java; the ovate thicker shells come from several localities in the south of East Java, from the islands of Nusa Tenggara, and in Sulawesi waters. The largest globose and slightly thick M. gajahmadai n. sp. was found in the south of Nusa Penida Island, Bali with a shell length of 407.5 mm, and was found together with an ovate and thick specimen with a vivid red internal aperture taken from a lobster net set at a depth of 80 m. Three fossil specimens from Pasir Ipis, West Java and one from Sangiran, Central Java were examined: shell length 75.9-162.6 mm; spines 10-12, spine length 5.2-9.8 mm; protoconch 3,5 whorls, diameter 12.4-13.8 mm, height 6.6-7.6 mm; height of the fossil protoconch is slightly higher than the recent. These four fossil specimens were sub-adult or juvenile, and assigned to Melo gajahmadai n. sp. Compared to Melo ashmorensis Morrison & Wells, 2005, M. gajahmadai n. sp. has fewer spines (7-12) but they are relatively longer (6-16 mm) than in M. ashmorensis which has 13-16 shorter spines (4-8 mm). M. amphora has a thick to very thick shell, longer and slender spines of 7-24 mm which are relatively erect and spaced further apart, the shell of M. gajahmadai n. sp. is thinner, the length of the spines shorter of 6-16 mm and the spines are broad at the base, slightly curved to the protoconch and more closely spaced. In M. umbilicatus the shell is compressed, the apex depressed, the spire and the protoconch sunken, has few (5-9) and long spines (14-31 mm), and the posterior outer lip extends upwards with the top an inverted 'V shape. The shell of M. aethiopicus is generally globose in shape, the posterior outer lip extends upwards, and has more spines (12-18) than in M. gajahmadai n. sp. which is more variable in shape, some are ovate or globose, the posterior outer lip relatively flat, and the number of spines is 7-12. In contrast, the shells of M. gajahmadai n. sp. do not show a development of the outer lip as in M. aethiopicus. M. aethiopicus and M. gajahmadai n. sp. can be found together in Barrang Lompo Islands, South Sulawesi; and Banggai Islands, Central Sulawesi.
In a comparison of the two new species described herein, Melo nusantara n. sp. has fewer spines (5-9) than M. gajahmadai n. sp. which has 7-12 spines. Termination of spines on mature shells of M. nusantara n. sp. is at the outer lip or to the last quarter whorl, while in M. gajahmadai n. sp. usually the spines do not reach the outer lip but only to the last quarter or half of the last whorl. In M. gajahmadai n. sp. the upper part of the shoulder is sharp or slightly sharp. The final difference is the colour of the adult shells of M. nusantara n. sp. which is a uniform light cream without spots, in contrast to M. gajahmadai n. sp. which has either two spiral brown bands, two rows of spiral dark brown spots, a zigzag pattern, or occasionally a white marbled pattern. The two new species, M. nusantara n. sp. and M. gajahmadai n. sp. live south of Cilacap, Central Java, Indian Ocean.

Type locality. Puger, south of East Java, Indonesia. Distribution. Fossil specimens of Melo gajahmadai n. sp. are found in Pasir Ipis, West Java, Middle Pliocene, and Sangiran, Central Java, Late Pliocene.
The recent specimens live from the south of Central and East Java, Indian Ocean; Bali Strait, south of Bali and the Nusa Tenggara Islands such as Lombok, Sumbawa, Flores, Adonara, and Timor; Barrang Lompo Islands and Pangkajene Islands in South Sulawesi waters; Banggai Islands in Central Sulawesi .
Habitat. On muddy sand, dived by fishermen from shallow waters to a depth of 45 m and from lobster nets in Puger, south of East Java, Indian Ocean to a depth of 120 m.
Etymology. The name given to Gajah Mada (1290-1364), a "mahapatih" or prime minister of the Majapahit kingdom in Java in the 14th century.