minor things
diff --git a/Doc/libselect.tex b/Doc/libselect.tex
index 421d1aa..0b50101 100644
--- a/Doc/libselect.tex
+++ b/Doc/libselect.tex
@@ -12,14 +12,14 @@
\code{perror()}.
\end{excdesc}
-\begin{funcdesc}{select}{iwtd\, owtd\, ewtd\, timeout}
+\begin{funcdesc}{select}{iwtd\, owtd\, ewtd\optional{\, timeout}}
This is a straightforward interface to the \UNIX{} \code{select()}
system call. The first three arguments are lists of `waitable
objects': either integers representing \UNIX{} file descriptors or
objects with a parameterless method named \code{fileno()} returning
such an integer. The three lists of waitable objects are for input,
output and `exceptional conditions', respectively. Empty lists are
-allowed. The optional last argument is a time-out specified as a
+allowed. The optional \var{timeout} argument specifies a time-out as a
floating point number in seconds. When the \var{timeout} argument
is omitted the function blocks until at least one file descriptor is
ready. A time-out value of zero specifies a poll and never blocks.