Don,

I can't give you a straight answer about what is happening, but I noticed a couple of things:

* SYN-packets are sent to ports on the receiving host, but there is no answer from this host (host down, or is it ignoring the other host/ these ports?)
* the packets are sent to the same 10 ports in a specific order.
* this cycle is repeated. Every new cycle, the packets are sent from another port
* The receiving ports are not used very commonly.

I would say it is some sort of portscan, but then, why is it only scanning ports that probably are closed because they are not used by commonly used services?

My guess is that this is one of the tests for an OS-detection, but it might even by some sort of complex handshake or authentication procedure (like Kerberos).

I hope you will post the answer soon.