diff --git a/docs/cmu-user/extensions.tex b/docs/cmu-user/extensions.tex
index c5da4a24945b036ef991f454d8fa9687db503769..ad0d260a452c6b2735f017aceaf36eb57071d9cc 100644
--- a/docs/cmu-user/extensions.tex
+++ b/docs/cmu-user/extensions.tex
@@ -1000,7 +1000,7 @@ specialized arrays.  Thus
 \end{defvar}
 
 \section{Stream Extensions}
-\begin{defun}{extensions:}{read-n-bytes}{%
+\begin{defun}{sys:}{read-n-bytes}{%
     \args{\var{stream buffer start numbytes} 
       \ampoptional{} \var{eof-error-p}}}