Figure 11.2. Exposing the ganglia (HelisomaLymnaea). A. Cut along the spiral of the shell for about one full turn, breaking it away as you go. Try not to cut deeply into the snail’s body, but do not worry if body fluid leaks. If the shell breaks apart completely, you may need help orienting the body for the next step. B. Place the snail with its foot down in a dish and secure it with pin 1. If you have trouble finding the foot, the body may be twisted. Rearrange it and move pin 1 as needed. C. Put pins 2 and 3 though the foot, going under each tentacle. D. Pull the mantle back and place pins 4 and 5 to hold it. Remove pin 1. E. Cut through the mantle toward the head, starting between pins 4 and 5. Cut into the body cavity but make the cut shallower as you approach the end. Afterwards, the red buccal mass should be evident, with the cerebral ganglia just behind it. Move pins 2 through 5 to spread the skin. (This diagram does not show organs that may need to be moved aside to reveal the ganglia.) F. Cut the esophagus behind the cerebral ganglia. Pull the esophagus through the ganglion ring, tilt the buccal mass forward, and place pin 6 through the esophagus. You may need to twist the buccal mass slightly to put the buccal ganglia on top.
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