diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index a5c1501f614a6e2650b14edc84eb5564ded1e2f7..0c43954d81572a43818cece822eb9a7029412e3f 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1036,12 +1036,12 @@ def resource(*resources, &block)
         #
         # This generates the following comments routes:
         #
-        #   GET     /photos/:id/comments/new
-        #   POST    /photos/:id/comments
-        #   GET     /photos/:id/comments/:id
-        #   GET     /photos/:id/comments/:id/edit
-        #   PUT     /photos/:id/comments/:id
-        #   DELETE  /photos/:id/comments/:id
+        #   GET     /photos/:photo_id/comments/new
+        #   POST    /photos/:photo_id/comments
+        #   GET     /photos/:photo_id/comments/:id
+        #   GET     /photos/:photo_id/comments/:id/edit
+        #   PUT     /photos/:photo_id/comments/:id
+        #   DELETE  /photos/:photo_id/comments/:id
         #
         # === Options
         # Takes same options as <tt>Base#match</tt> as well as: