Molluscs have long been a focus for both amateur and professional naturalists. The distinctive, calcareous forms of seashells make them ideal for collection and classification. Unsurprisingly, shells from southern oceans were among the first Australian species to become known in Europe.
While a scientific generalist, Frederick McCoy had particular expertise in palaeontology. He was interested in living molluscs, especially Trigonia, which survived around Victoria's coast and were represented by related species in fossil records of both Australia and Europe. While evolutionists used the Trigonia as evidence for their theory, McCoy maintained a staunchly anti-Darwinist stance throughout his career.
McCoy commissioned illustrations of fossil shells for his Prodromus of the Geology of Victoria, but resisted the temptation to illustrate many living species. Keen to make the most of his unique geographic and historic position, he avoided expending resources on animals already adequately covered in the scientific literature.
Consequently the Prodromus of Zoology includes only four species of living molluscs. All cephalopods, they were the Paper Nautilus, the Southern Calamari, the Giant Cuttlefish and the Arrow Squid. Unpublished plates revealed another Giant Cuttlefish series, featuring a smaller and somewhat fresher specimen. While few species were illustrated, McCoy and his artists were clearly interested in cephalopods, dedicating multiple individual plates to each species.
Arthur Bartholomew also created a unique set of 25 illustrations of freshwater snails and land molluscs. Drawn from live animals in the laboratory, these reveal the texture and colour of animals rarely illustrated in such detail. Some were indigenous, such as the carnivorous land snail collected from Kew, while others like the Leopard Slug were recent introductions, and may be the first record of the animal in Australia.