diff --git a/Changelog.md b/Changelog.md
index 496871fc..33935dbe 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -2,7 +2,7 @@
 
 * Remove invalid mutation `foo or bar` to `!(foo or bar)` see #287
 * Add mutation from `#to_h` to `#to_hash` #218
-* Add mutation from `#defined?` to `true` / `false` #399
+* Add mutation from `#defined?` to `true` / `false` #334
 
 # v0.8.1 2015-07-24
 
diff --git a/lib/mutant/mutator/node/defined.rb b/lib/mutant/mutator/node/defined.rb
index 8aaffa8d..cb01f494 100644
--- a/lib/mutant/mutator/node/defined.rb
+++ b/lib/mutant/mutator/node/defined.rb
@@ -16,21 +16,10 @@ module Mutant
         #
         # @api private
         def dispatch
-          emit_expression_mutations do |node|
-            !n_self?(node)
-          end
-
-          emit_bools
-        end
-
-        # Emit booleans
-        #
-        # @return [undefined]
-        #
-        # @api private
-        def emit_bools
+          emit_singletons
           emit(N_TRUE)
-          emit(N_FALSE)
+
+          emit_expression_mutations { |node| !n_self?(node) }
         end
 
       end # Defined
diff --git a/meta/defined.rb b/meta/defined.rb
index e61d8af7..48214224 100644
--- a/meta/defined.rb
+++ b/meta/defined.rb
@@ -1,7 +1,7 @@
 Mutant::Meta::Example.add do
   source 'defined?(foo)'
 
+  singleton_mutations
   mutation 'defined?(nil)'
   mutation 'true'
-  mutation 'false'
 end