Placostylus hongii is a species of very large, air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Bothriembryontidae.

[2] The length of the shell attains 75 mm.

This species is endemic and occurs in New Zealand.

[3] Placostylus hongii is classified by the New Zealand Department of Conservation as Range Restricted.

[4] Buckley et al. (2011)[5] from short sequence molecular phylogeny and shell dimensions, that there are no subspecies of Placostylus hongii.