The snail's central nervous system extensively pinned out.  .

 

These are the subesophagial ganglia stained with Fast Green.  You can see that snail neurons come in many sizes.  Those unstained round granular areas on either side of the ganglia are sensory elements that help the snail know which way is up!.

Some snail neurons contain granules that fluoresce under UV light when exposed to formaldehyde.  The glowing neurons here contain serotonin.

 

These dark cells have been filled with cobalt by dipping their cut axons in a cobalt solution.  You can see the axons coming off the neurons .

 

This is the eyestalk of a snail.  We stained this for fun.

 

We're trying to figure out the neural circuitry of the focal withdrawal response to radiant heat.  Since this is organized in the foot, we've had to start dealing with this muscular structure.  The large objects here, stained with Fast Blue, secrete the slime snails glide on.

 

Using fluorescence microscopy and an unnamed stain, the secretory cells (green) stand out quite dramatically.  This image was taken just for fun too.