I'm trying to
  1) go through a set of nodes
  2) if any matches my criteria, display it
  3) if NONE matches my criteria, display a message like "None"

For example, imagine this xml listing some animals:
<animal>
  <type>snake</type>
  <furry>false</furry>
</animal>
<animal>
  <type>fish</type>
  <furry>false</furry>
</animal>

and this XSL that lists all the ones with fur:
The following animals are furry:<br/>
<xsl:for-each select="animal">
  <xsl:if test="furry = 'true'">
    <xsl:value-of select="type"/><br/>
  </xsl:if>
</xsl:for-each>
[if no animals were furry, print "None are furry"]  <---how can I do this?