<p>When I searched the NCBI Taxonomy db for id=693 it has retrieved the result but the tax_id in the result is different by the ID which I searched
<a href='http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=taxonomy&amp;id=603&amp;retmode=xml'>http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=taxonomy&amp;id=603&amp;retmode=xml</a></p>

<p>and I just find out this tax_id (603) is related to gi=156763600 on gi_taxid_prot.dmp.gz and If you search it on <a href='http://www.ncbi.nlm.nih.gov/protein/156763600'>ncbi</a> and press Taxonomy from the right part of the page it comes by error on the next page.</p>

<p>Have you any explanation for these!?</p>

<p>I assume you mistyped the first taxonomy ID and meant <code>603</code> instead. When you are using NCBI's web-search form, then a search for the ID <code>603</code> will redirect you to <a href='http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&amp;id=59203&amp;lvl=3&amp;lin=f&amp;keep=1&amp;srchmode=5&amp;unlock'>Salmonella enterica subsp. arizonae</a>, which coincides with the XML query result you linked to. Said Salmonella has taxonomy ID <code>59203</code> just as in the XML result.</p>

<p>The taxonomy IDs <code>603</code> and <code>59203</code> appear to be denoting the same database entry, which is reflected in the XML at the bottom with:</p>

<pre><code>[AkaTaxIds]
    [TaxId]603[/TaxId]
[/AkaTaxIds]
</code></pre>

<p>I think you can treat taxonomy IDs <code>603</code> and <code>59203</code> as synonyms.</p>

<p>Hope that helps.</p>
