Thaliacea \Tha`li*a"ce*a\, n. pl. [NL. See Thalia.]

(Zo["o]l.) A division of Tunicata comprising the free-swimming species, such as Salpa and Doliolum.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Vertebrata, including Mammalia or Mammals, Aves or Birds, Reptilia, Amphibia, Pisces or Fishes, Marsipobranchiata (Craniota); and Leptocardia (Acrania). Tunicata, including the Thaliacea, and Ascidioidea or Ascidians. Articulata or Annulosa, including Insecta, Myriapoda, Malacapoda, Arachnida, Pycnogonida, Merostomata, Crustacea (Arthropoda); and Annelida, Gehyrea (Anarthropoda).

Source: Webster's Revised Unabridged Dictionary (1913)