Some emails which come from anonymous emails dont have any ip so no one can trace where they are coming from, beware of such emails as they could be spam and virus infected.
Try to type 'emails without ip addresses' in google and you might find articles with more details in them.
X-originating is not a standard email header. In fact, any header record beginning with X- is non-standard. That's the standard prefix for non-standard header records
The only place where you can definitely trust an IP address in an email is the very first Received: record in a header (that's because that is the one your MTA included, i.e. where it got the message from). All other Received: header records could be forged.