dissepiment
From ZooTerms (Dictionary of Invertebrate Zoology)
dissepiment (noun; plural dissepiments; Latin dissaepire, to separate): 1. A partitioning wall; a septum.
2. (Arthropoda: Insecta) a. The septa of an embryo, separating the coelom-sacs. b. The enclosing membrane of an obtect pupa.
3. (Cnidaria: Anthozoa) A transverse calcareous plate or partition between the radiating septa of coral.
4. (Sipuncula) A series of peritoneal tissue situated transversely across the coelom.
