Please answer the following question: Information:  - Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word "slug" is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semislugs (this is in contrast to the common name "snail", which applies to gastropods that have a coiled shell large enough that the animal can fully retract its soft parts into the shell).  - Discodorididae is a taxonomic family of sea slugs , specifically dorid nudibranchs , marine gastropod mollusks in the superfamily Doridoidea . Species in this family belong to the cryptobranch dorid nudibranchs , i.e. they are able to retract their gills into a gill pocket ( cryptobranch = hidden gills ) . Most are small and hard to identify . Most are thought to feed at night on sponges , while during the day they search for dark areas or remain hidden under rocks . One example of a discodoridid is the `` Pacific sea lemon '' or `` speckled sea lemon '' , Peltodoris nobilis , which occurs off the coast of British Columbia to Baja California from low - tide waters to a depth of about 200 m. Not only is this species yellow with a bumpy surface , but it also gives off a strong fruity citrus smell when handled , adding to its resemblance to a lemon .  - Doridacea is a taxonomic grouping of dorid nudibranchs, shell-less marine gastropod mollusks. included in the clade Euctenidiacea of the clade Nudibranchia.  - Doridoidea, commonly known as dorid nudibranchs (and previously known as the taxon Cryptobranchia), are a taxonomic superfamily of medium to large, shell-less sea slugs, marine gastropod mollusks in the clade Doridacea, included in the clade Nudibranchia.    Given the information, choose the subject and object entities that have the relation of 'parent taxon'.
Answer:
discodorididae , nudibranchia