endoderm
From ZooTerms (Dictionary of Invertebrate Zoology)
endoderm (noun; Greek endon, within; derma, skin): 1. The innermost cell layer of the embryo forming the epithelium of the archenteron, endoblast, entoderm, and hypoblast.
2. (Cnidaria) Layer of cells lining the gastrovascular cavity.
3. (Porifera) see pinacoderm.
