Keys provide listings of character states and images of those states. They are constructed to distinguish taxa within successively smaller taxonomic groupings (starting with the family level for the Acoela).

Once a group is selected, characters relevant to it are displayed. Clicking on any one of those characters displays a listing of relevant character states from which selections can be made to display both the morphology of the character state and the taxa to which that state applies. Selecting a character state will modify the list of taxa, excluding those to which the state does not apply and leaving a list of "Remaining taxa" to which it does.

Illustrations of character states are available for selected groups. These appear in the upper right box of the key when the image symbol is selected for that state. (Work in progress).

Clicking on the hyperlink for any taxon listed in the right-hand column (Conaperta in this example) opens another window with hyperlinks to further images of member taxa and hyperlinks allowing selection of images of related taxa as well as hyperlinks back to the main taxonomic tables with diagnoses and notes.