Comb rows run along the aboral edge. These vicious beasts have the habit of using a large mouth to consume other comb jellies with reckless abandon. Like cnidarians, comb jellies are at the tissue level of organization. The body exterior is covered with a thin ectoderm that enters the mouth and lines the pharynx. The ctenophore mouth consists of a narrow slit, which leads into the compressed stomodaeum, or stomach formed by endodermal tissue.
Extracellular digestion begins in the pharynx, with further digestion in the stomodaeum.
Partially digested food is then distributed throughout the body by complex systems of gastrovascular canals. These canals are lined with endodermal cells that complete digestion of food materials intracellularly. The canals extend into eight meridional canals that lie directly under each comb row, and run through the gelatinous mesoglea that forms the bulk of the body between the ectoderm and endoderm. Connective tissue fibers, muscle cells and wandering ameboid cells help to add substance to the mesoglea. Muscle cells underlie the ectoderm, and are concentrated in the tentacles, the area around the mouth and pharynx, and surrounding the aboral area.