diff --git a/recaptcha.module b/recaptcha.module
index 7e7d465..83ae123 100644
--- a/recaptcha.module
+++ b/recaptcha.module
@@ -73,15 +73,12 @@ function recaptcha_permission() {
 /**
  * Implements hook_captcha().
  */
-function recaptcha_captcha() {
-  $args = func_get_args();
-  $op = array_shift($args);
+function recaptcha_captcha($op, $captcha_type = '') {
   switch ($op) {
     case 'list':
       return array('reCAPTCHA');
 
     case 'generate':
-      $captcha_type = array_shift($args);
       $captcha = array();
       if ($captcha_type == 'reCAPTCHA') {
         // Retrieve configuration variables.