Naef, 1916
Description of ordinal characters
Shell calcareous (Genera Sepia and Spirulea), or chitinous (Family Sepiolidae), or absent. Eight arms and two tentacles. Tentacles retractile into pockets (Family Sepiidae); suckers with chitinous rings. The fin lobes are free posteriorly and not connected at the midline. The eyes are covered with a cornea (not in Spirulea). Gills without branchial canal between afferent and efferent branchial blood vessels. The digestive gland is paired. Radula with a single cusp. Buccal membrane present. The olfactory organ is a ciliated pit or a flat wart that is partially covered by a protective epithelium.
Hatchlings
Members of the Sepioidea hatch as miniature adults (except Spirula) — the newly hatched young show most of the adult characters. Characters for the identification of juveniles are therefore similar to those used for the identification of adults.
[After Lu et al. in Sweeney et al., 1992 ]
The following sepioid species are included:
Order Sepioidea
Family Sepiidae
Sepia elegans
Sepia officinalis
Sepia orbignyana
Sepiella japonica
Family Sepiolidae
Rossia macrosoma
Rossia palpebrosa
Sepietta neglecta
Sepietta oweniana
Sepiola atlantica
Sepiola aurantiaca