The parameter estimates do not show the parameter estimate for the last category of a categorical variable due to the way the coding of that variable is done. That last category is -1*(sum of the other parameter estimates). In the example, 50.9 + -11.9 = 39.0 (with rounding, of course). Therefore, mathematically, you do not need to display the last parameter estimate (in actuality, it is not displayed because of the way the mathematics are done).
Anyhow, this is why JMP offers the Prediction Equation option. You can also see it in the Expanded Parameter Estimates table, available from the red popup menu choosing Estimates > Expanded Estimates.
Dan Obermiller