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Related to Ascidiacea: Larvacea, Thaliacea


[From New Latin Ascidia, genus name, from Greek askidion, diminutive of askos, wineskin.]


1. (Zoology) any minute marine invertebrate animal of the class Ascidiacea, such as the sea squirt, the adults of which are degenerate and sedentary: subphylum Tunicata (tunicates)
2. (Zoology) ascidian tadpole the free-swimming larva of an ascidian, having a tadpole-like tail containing the notochord and nerve cord
(Zoology) of, relating to, or belonging to the Ascidiacea


(əˈsɪd i ən)

1. any tunicate of the class Ascidiacea, having in the larval stage a notochord, a characteristic of the embryonic vertebrate.
2. belonging or pertaining to the class Ascidiacea.
[1855–60; < New Latin Ascidi(um) a tunicate genus < Greek askídion a small bag + -an1]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.ascidian - minute sedentary marine invertebrate having a saclike body with siphons through which water enters and leavesascidian - minute sedentary marine invertebrate having a saclike body with siphons through which water enters and leaves
tunicate, urochord, urochordate - primitive marine animal having a saclike unsegmented body and a urochord that is conspicuous in the larva
Ascidiaceae, class Ascidiaceae - sometimes classified as an order: sea squirts
sea squirt - ascidian that can contract its body and eject streams of water
References in periodicals archive ?
Belonging to phylum Chordata, class Ascidiacea, these invertebrates have tissue and organ complexity incipient to that of vertebrates (see Fig.
Members of the class Ascidiacea were not considered in this study because this taxon was excluded during the first years of sampling.
3 All crabs 2 3 Majidae Oregoniidae, Chionoecetes bairdi Chionoecetes opilio 3 Hyas lyratus 2 All Sipuncula 3 All Echiuridae 19 27 All Bryozoa Clypeasteroida, sand dollar 2 All Ascidiacea, tunicates 7 Chelysoma spp.
The species sampled include more than one member of each of the three orders in class Ascidiacea, providing substantial diversity for comparative research.
The evolution and distribution of Australian tropical Ascidiacea.