acœlomata

from The Century Dictionary.

• A division of Protocælomata, or sponges, containing the Ascones: so called in allusion to its pores and the absence of cœlomata.
• The cœlenterates and sponges considered collectively as animals without a true cœloma, or body-cavity, as distinct from the enteron or digestive cavity. Many zoölogists regard the Metazoa as consisting of two great primary groups: the Acœlomata, or sponges and cœlenterates, and the Cœlomata, or all the remaining Metazoa.