| Abstract: | The olfactory system of the snail is functionally capable andstructurally complex. The morphology of the olfactory epitheliumand the glomeruli are similar to analogous structures in vertebrates.However, the snail system differs markedly from the vertebratesystem in its lack of a mucus secretion and the apparent absenceof spatial patterning. Such similarities and differences teachus about the limitations and options governing the evolutionof olfactory systems. The comparative approach leads to thefollowing conclusions, or lessons: (1) Death andreplacement is normal for olfactory receptors. (2) Olfactionrequires large numbers of receptors and other neurons. (3) Glomerularstructures in the olfactory neuropil aid sensory processing.(4) Local interactions are important in the early stages ofolfactory processing. (5) The role of mucus in olfaction ispeculiar to the vertebrate nose. (6) The spatial patterningof odor responses is not necessary for effective odor processing. |
