diff --git a/src/java/com/threerings/presents/io/StreamableUtil.java b/src/java/com/threerings/presents/io/StreamableUtil.java
index 2a1cd6d21..98b0d063f 100644
--- a/src/java/com/threerings/presents/io/StreamableUtil.java
+++ b/src/java/com/threerings/presents/io/StreamableUtil.java
@@ -1,5 +1,5 @@
 //
-// $Id: StreamableUtil.java,v 1.2 2002/03/20 22:58:26 mdb Exp $
+// $Id: StreamableUtil.java,v 1.3 2002/03/20 23:08:22 mdb Exp $
 
 package com.threerings.presents.io;
 
@@ -100,6 +100,13 @@ public class StreamableUtil
             // get the next streamable to write out
             Streamable s = values[ii];
 
+            // if this index is empty, write -1 as the class identifier to
+            // indicate such
+            if (s == null) {
+                out.writeShort(-1);
+                continue;
+            }
+
             // look up the class id
             cname = s.getClass().getName();
             short cidx = (short)ListUtil.indexOfEqual(cnames, cname);
@@ -154,6 +161,12 @@ public class StreamableUtil
             // read the class id number
             short cidx = in.readShort();
 
+            // if the class identifier is -1, that means this is a null
+            // element
+            if (cidx == -1) {
+                continue;
+            }
+
             // look up the class name
             String cname = (cidx > cnames.length - 1) ? null :
                 (String)cnames[cidx];