make-list-reader

[John Hodgkinson <Hodgkinson@YALE.ARPA>]

I am attempting to use MAKE-LIST-READER, mentioned on pp 76-77
of the T Manual, 4th ed.  According to the manual, the list-reader 
created by MAKE-LIST-READER has two arguments, the first a
stream and the second, whatever it is, ignored.  When I invoke a
list-reader with two such arguments, though, I get a valency error:

> (let ((my-tab (make-read-table *standard-read-table* 'my-tab))
        (my-paren (make-list-reader))
        (left-count 0))
    (set (read-table-entry my-tab #\left-paren)
         (object (lambda (str ch)
                   (increment left-count)
                   (my-paren str ch))
                 ((delimiting-read-macro? self) t)))
    (with-input-from-string (str "( hi (there))")
      (set (stream-read-table str) my-tab)
      (read str)))

** Error: wrong number of arguments to procedure
  (#{List-reader 13} #{String-input-stream 14} #\()
>> (argspectrum (make-list-reader))
(3)

What should this third argument be?

Thanks in advance.