VB in it’s classic state (pre .Net) had an Integer data type. So, in VB.Net you can still use Integer in the syntax (Dim x As Integer) but it will be using a System.Int32. Now, if you try to do a Type.GetType(“System.Integer”) it will return a null value whereas Type.GetType(“System.Int32”) will correctly return a type initialized to Int32. If you’re dynamically creating types then using the GetType to the appropriate CLR type is a must. Here are two links, one for .Net 3.5 and one for .Net 4.0 showing the data types.
For posterity, here is the table reference in case the above links stop working: