"The expodites are left out because entirely unknown."

"Walcott in his study of trilobites in thin section (1881, pp. 192, 206, pl. 2, fig. 9) obtained eleven slices of Isotelus gigas which showed remains of appendages.
He figured one of the sections, stating that it "shows the basal joint of a leg and another specimen not illustrated gives evidence that the legs extended out beneath the pygidium, as indicated by their basal joints.""