--- a/doc/catalogs.txt
+++ b/doc/catalogs.txt
@@ -170,15 +170,15 @@
 
 .. code-block:: python
 
-    def extract_xxx(fileobj, keywords, comments_tags, options):
+    def extract_xxx(fileobj, keywords, comment_tags, options):
         """Extract messages from XXX files.
         
         :param fileobj: the file-like object the messages should be extracted
                         from
         :param keywords: a list of keywords (i.e. function names) that should
                          be recognized as translation functions
-        :param comments_tags: a list of translator tags to search for and
-                              include in output
+        :param comment_tags: a list of translator tags to search for and
+                             include in the results
         :param options: a dictionary of additional options (optional)
         :return: an iterator over ``(lineno, funcname, message, comments)``
                  tuples