“ The presence of jurisdiction upon petition for writ of certiorari does not, of course, determine the exercise of that jurisdiction, for the issuance of the writ is discretionary. In this case petitioner could have obtained review of the final adjudication of the merits by appealing from the default judgment. The California Supreme Court has apparently refrained from taking action because of the existence of that remedy. In these circumstances we think it advisable not to exercise our jurisdiction. ”

“ After argument, we continued this cause to enable the petitioner to apply for a certificate or other expression from the appropriate California courts to show whether the judgments rested on adequate and independent state grounds or whether decision of the federal question was necessary to the judgments rendered. ”