RESUMO
Nembutal, menthol, Ketaset, and Curarine were used to anesthetize beta race of Tricula aperta snails in preparation for study by scanning electron microscopy. The snails remained sensitive to the glutaraldehyde fixative in low level anesthesia of nembutal, menthol and Ketaset. Snails were also sensitive to Curarine and retracted into their shells. The best relaxations were obtained by initial anesthesia with nembutal or menthol followed by curarine. Snails relaxed by this procedure showed relatively little reaction to the fixative solution and remained extended outside their shells. The surface ultrastructure of the snails was well preserved, showing microvillate, secretory, and ciliated sensory cells. The mucoid secretions remained on the surface of cilia on the body and foot of the snails as spherical granules. There were two types of ciliated cells: (1) Those with few short cilia showing 1-3 microns above the microvilli of surrounding cells and (2) Those with numerous cilia up to 10 microns long. Results of transmission electron microscopic studies of these snails show no disruption of the ultrastructure of the surface cells.