Diagnosis
Shell subglobose, 17.4-25.2 mm in height and 23.5-29.9 mm in width. Shell generally pale yellow to tan, with broad red umbilical patch and broad red subsutural band; inner lip pale pink to mauve. Mantle colour orange. Penis and vagina long, about equal in length.
Description
Shell : Subglobose, 17.4-25.2 mm in height and 23.5-29.9 mm in width. Spire moderately elevated. Aperture roundly ovate, height 12.3-15.9 mm and width 15.1-20.1 mm. Total number of whorls 5.3-6.1. Last teleoconch whorl rounded, or with slight peripheral angulation; height 14.7-20.2 mm. Teleoconch sculpture of fine to well developed growth lines. Teleoconch periostracal sculpture of weak zigzag ridges, with minor sculpture between major ridges. Protoconch sculpture weakly pustulose. Shell pale yellow (typical) to tan, with broad red umbilical patch and broad red subsutural band, sometimes with an additional red supraperipheral band; (darker specimens appear to be uniform brown but still retain hints of the umbilical and subsutural bands). Inner lip pale pink to pale mauve; strongly reflected to partially obscure umbilical depression. Outer lip moderately deflected below midline of last whorl. Umbilicus typically closed, sometimes slightly open. Dimensions of Lectotype: SH—18.8 mm, SW—26.1 mm, AH—13.6 mm, AW—16.6 mm, BW—17.2 mm, TW—5.50 whorls. Non-genital Anatomy. Animal and mantle colouration orange. Kidney approximately 50-59% of length of mantle roof.

The first reference to this species is by Pfeiffer (1846b), where he simply referred to it as "Helix ..." and gave a reference to two figures that Gray sent him, however, these figures were never published (Pilsbry, 1893:281). He then named the species in 1848 and illustrated it in 1851 (Pfeiffer 1851c). The figured specimens are similar in shell form to those commonly encountered from the central coast of New South Wales. Based on the material examined in the present study it is considered that the material before Pfeiffer most likely originated from the Gosford area rather than further north, and hence the type locality is restricted to Wyee Point, Lake Macquarie, S.E. of Morisset, a little north of Gosford, although the source of the original material cannot be established with certainty. There is some variation, particularly in shell size and colour, among the populations tentatively included under this taxon and it is possible that more than one species is present. Morphological and molecular study of new material may thus reveal cryptic taxa.
Meridolum grayi is similar to M. jervisensis but is generally larger with up to six whorls and is slightly more globose. In comparison to M. middenense, M. grayi is larger and has a more elevated spire. It is much larger than M. maryae n. sp. and M. sheai n. sp. and smaller than M. gulosum and M. marshalli. In addition there are distinctive 16S mitochondrial DNA sequences differences between the species (Clark 2005).
The name Helix grayi is most commonly encountered in the very early literature. Pfeiffer (1851b) indicated that while Helix grayi, H. jervisensis and H. sutilosa superficially resembled each other, he nonetheless thought that they represented separated taxa. Pilsbry (1894) was the first to synonymise H. grayi under H. jervisensis in the genus Thersites Pfeiffer, 1855. Iredale (1938) considered H. grayi a synonym of Helix gilberti in the genus Meridolum. In the more recent literature (e.g. Smith 1992) H. grayi is generally considered of uncertain status, with the taxon cited as being based on poorly localised material from the east coast of Australia.

Meridolum grayi (Pfeiffer, 1846) appears to be restricted to the moist forests of the central coast of New South Wales between the Hawkesbury River and the Hunter River. It is found mainly under fallen palm fronds and in leaf litter. Meridolum grayi has also been found in suburban gardens bordering native forest.