APM: shift question

[Goldilox]

How come I can go

$x=shift @array;

and $x is equal to the first array element, but

shift @array;

doesn't put the first element to $_?

I tried printing $_:

#!/usr/bin/perl -w
use CGI;
$cg=new CGI;
print $cg->header;
@directories = qw(01Jan 02Feb 03Mar 04Apr 05May 06Jun 07Jul 08Aug 09Sep 10Oct
11Nov 12Dec);
print "Here ", at directories,"<br>";
shift @directories;
print "Here is \$_: $_";
print $_;

and it is empty. Any hints?

Rhett