diff --git a/demos/custom-fields/field_turtle.js b/demos/custom-fields/field_turtle.js
index dc7b8c8ea..f31989dff 100644
--- a/demos/custom-fields/field_turtle.js
+++ b/demos/custom-fields/field_turtle.js
@@ -29,6 +29,7 @@ goog.provide('CustomFields.FieldTurtle');
 
 // You must require the abstract field class to inherit from.
 goog.require('Blockly.Field');
+goog.require('Blockly.fieldRegistry');
 goog.require('Blockly.utils');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.Size');
@@ -533,7 +534,7 @@ CustomFields.FieldTurtle.prototype.fromXml = function(fieldElement) {
 
 // Blockly needs to know the JSON name of this field. Usually this is
 // registered at the bottom of the field class.
-Blockly.utils.fields.register('field_turtle', CustomFields.FieldTurtle);
+Blockly.fieldRegistry.register('field_turtle', CustomFields.FieldTurtle);
 
 // Called by initView to create all of the SVGs. This is just used to keep
 // the code more organized.
@@ -742,4 +743,4 @@ CustomFields.FieldTurtle.prototype.createView_ = function() {
       'stroke': '#000',
       'stroke-opacity': .3
     }, this.stripesPattern_);
-}
+};