Crabs, lobsters, slaters, shrimps, barnacles and woodlice are all Crustacea. Together they comprise a diverse sub phylum of Arthropoda. Most Crustacea are found in marine habitats, while others live in freshwater. A relatively small number have adapted to terrestrial environments.
A total of seven species of Crustacea were included in the Prodromus. They include the largest and most commercially important species, such as the Murray Spiny Crayfish, Southern Rock Lobster and Tasmanian Giant Crab.
Several other species were illustrated in unpublished plates, including highly detailed studies of a burrowing crayfish prepared by John James Wild and two intriguing illustrations of spiny crayfish. It is clear from McCoy's earlier descriptions of the Yarra Spiny Crayfish that he was becoming increasingly aware that each major Victorian watershed had its own variety of crayfish; unfortunately he never provided descriptions of the unpublished plates.
Studies by Arthur Bartholomew highlight other specimens from an area that is now suburban Melbourne. The yabby from a quarry in Brunswick and an impressive prawn from Mordialloc are examples of familiar fauna from locations that have changed profoundly in the last 150 years.