Detailed petrographic analysis of the type specimens of Cambrian Archaeotrypa prima and A. secunda shows that A. prima differs in important features from the original description. The tubes that make up the compound skeleton are twice as wide as thought previously, with an internal structure comprising both straight and zigzag longitudinal partitions and flat transverse partitions; the transverse partitions are staggered in vertical section and meet the zigzag longitudinal partitions. Archaeotrypa secunda differs very significantly from A. prima. The holotype of A. secunda is very poorly preserved, and consists of only a small tangential section comprising six complete and seven incomplete polygons. The genus Archaeotrypa and the species A. prima are retained, but the name A. secunda is restricted to the type specimen. The affinity of Archaeotrypa prima is uncertain, but it may be modeled as a cystoporate bryozoan or alternatively as an echinoderm.