Formation and evolution of the Galactic bulge and spheroid - Where did the spheroid gas go?

Several possible models for the evolution of the Galactic r exp 1/4 spheroid and bulge are discussed, with special attention given to the fate of the missing spheroid mass and the rate of star formation in the bulge. Attention is called to a possibility that the spheroid is chemically distinct from the disk and that the spheroid gas fell toward the center of the Galaxy and formed the central bulge, as suggested by angualr momentum considerations.