McCoy included three species of frog in the Prodromus of the Zoology of Victoria: the Growling Grass Frog, the Pobblebonk and the Spotted Marsh frog. The Growling Grass Frog received particular attention, with most life stages of the animal illustrated.
Several species of frogs were kept in the laboratory adjacent to McCoy's lecture room at the University of Melbourne. They were tended and illustrated by his lecture room assistant, Arthur Bartholomew, whose delightful images of living specimens are among the collection's highlights.
Bartholomew gave particular attention to the diagnostic attributes of each species, providing line drawings of the underside of the hand and foot, as well as the interior of the mouth.