Send a polymorphic object over serial
I think http://stackoverflow.com is the correct forum for your question. Your problem is how to serialize/deserialize correctly an object in C++. 

An easy way to do it is simply send the values (not the object) and recreate the object at the other side. So, now your problem is reduced to send and receive a bunch of int's, float's, string's, whatever.

Why you want/need to do that?