All known Cambrian and Ordovician dendroids and hydroids of Tasmania are reviewed.Protohalecium hallianumChapman & Thomas is revised at both generic and specific levels.Archaeocryptolaria rectavar.flexilisChapman & Thomas is revised toProtohalecium flexilis. Archaeolafoea serialis(Chapman & Thomas) (Hydroidea) is transferred toMastigograptus(Dendroidea). The following species are described as new:Acanthograptus antiquus(Cambrian),A. banksi, Desmograptus thomasi(Ordovician).