Registered 23,177 species  (Collections:372,143; Observations:73,075; Other records:4,293)
Classification : Eukarya - Opisthokonta - Animalia - Mollusca - Gastropoda - Orthogastropoda - Heterobranchia
真核生物ドメイン - Opisthokonta - 動物界 - 軟体動物門 - 腹足綱 - 直腹足亜綱 - 異鰓上目

Order Cephalaspidea   P. Fischer, 1883     頭楯目

Beesley, P. L., Ross, G. J. B. and A. Wells (1998) Mollusca: the southern synthesis. Fauna of Australia 5. CSIRO Publishing, Melbourne. 
Japan Oceanographic Data Center (2002) JODC taxonomic code of marine organisms (plankton). 2001 edition. In: Marine Organisms Data, accessed through 
Oskars, T. R., Bouchet, P. and M. A. Malaquias (2015) A new phylogeny of the Cephalaspidea (Gastropoda: Heterobranchia) based on expanded taxon sampling and gene markers. Molecular Phylogenetics and Evolution, 89, 130-150.