Unknown to scientists at the time, the body parts of relatives of "Anomalocaris" had already been described but not recognized as such. The first fossilized anomalocaridid mouth was discovered by Charles Doolittle Walcott, who mistook it for a jellyfish and placed it in the genus "Peytoia". Walcott also discovered a frontal appendage but failed to realize the similarities to Whiteaves' discovery and instead identified it as feeding appendage or tail of the extinct "Sidneyia". In the same publication in which he named "Peytoia", Walcott named "Laggania", a taxon that he interpreted as a holothurian.