Sponge
Like cnidarians (jellyfish, etc.) and ctenophores (comb jellies), and unlike all other known metazoans, sponges' bodies consist of a non-living jelly-like mass (mesoglea) sandwiched between two main layers of cells. Cnidarians and ctenophores have simple nervous systems, and their cell layers are bound by internal connections and by being mounted on a basement membrane (thin fibrous mat, also known as "basal lamina"). Sponges have no nervous systems, their middle jelly-like layers have large and varied populations of cells, and some types of cells in their outer layers may move into the middle layer and change their functions.
Channel catfish
Channel catfish possess very keen senses of smell and taste. At the pits of their nostrils (nares) are very sensitive odor-sensing organs with a very high concentration of olfactory receptors. In channel catfish, these organs are sensitive enough to detect several amino acids at about one part per 100 million in water. In addition, the channel catfish has taste buds distributed over the surface of its entire body. These buds are especially concentrated on the fish's four pair of barbels (whiskers) surrounding the mouth — about 25 buds per square millimeter. This combination of exceptional senses of taste and smell allows the channel catfish to find food in dark, stained, or muddy water with relative ease. They also possess a Weberian apparatus, which amplifies sound waves that would otherwise not be perceivable.