Four representative species of pinnipeds were studied with the purpose of clearly demonstrating the cerebral arterial circulation, and its variation, in this order of mammal. Special emphasis was placed on circulation to the eye. Arterial vessels to the head, exterior to the cranial vault, are also described. Species investigated were: Walrus, or Odobenus rosmarus; California Sea Lion, or Zalophus californianus; Harbor Seal, or Phoca vitulina; and Northern Elephant Seal, or Mirounga angustirotris. These species encompass the three families of the Pinnipedia. Vinyl casting with dissection and digestion of soft tissues was the method applied. A possible convergent evolutionary trend, environmentally induced, is noted in comparing circulation to the eye of pinnipeds with that of cetaceans. The conclusion of this study is a definition of the cerebro-cranial circulation in the Pinnipeds.