Rb_class_tbl - Odd Behavior

I was looking thru the code for defining a class.

1) I had a ruby program that generates two classes and a singular class.

2) Then I inserted into the code a direct call to rb_define_class().

NOW - The rb_class_tbl ONLY contains a reference to the class from 2)
              It does not contain references for the two classes from 1) 

Am I right is assuming this has to do with how the syntax tree is handled?
The references for 1) are in the syntax tree?

           Thanks