Genus Periscolex Cognetti, 1905, emend. Michaelsen 1918; Zicsi 1992.

Type species Periscolex mirus Cognetti, 1905 .

Diagnosis (based on Michaelsen 1918; Zicsi 1992). Arrangement of setae in eight rows per segment (lumbricine arrangement) or more than eight rows (perichaetine). Intraclitellar male pores. One pair of calciferous glands in segment vii with ribbed invaginations, with a large central lumen. Two testicular sacs and infundibula. Spermathecae present.

Remarks. Periscolex belongs to a group of genera formerly placed in Glossoscolecidae that were assembled in a separate family, based mainly on results of molecular phylogenetic studies (James & Davidson 2012); its valid name is Rhinodrilidae Benham, 1890 (James 2012).