/**
  * Returns a micro-species with the specified name or null otherwise.
  *
  * @param microSpeciesName
  * @return a species or null
  */
 @Override
 public ISpecies getMicroSpecies(final String microSpeciesName) {
   final ISpecies retVal = microSpecies.get(microSpeciesName);
   if (retVal != null) {
     return retVal;
   }
   final ISpecies parentSpecies = this.getParentSpecies();
   if (parentSpecies != null) {
     return parentSpecies.getMicroSpecies(microSpeciesName);
   }
   return null;
 }
 @Override
 public IExecutable getAspect(final String n) {
   return aspects.get(n);
 }
 @Override
 public WithArgs getAction(final String name) {
   return actions.get(name);
 }
 @Override
 public IVariable getVar(final String n) {
   return variables.get(n);
 }