Thirty-seven species of corals from the Gulf of California and North Pacific Coast are described and discussed. The list includes 14 new species and 6 genera not previously recognized in this area. For comparison a compiled list indicates at least 36 species in the Panamic area. No species was found common to the Gulf of California and North Pacific Coast faunas. Division between the two faunas occurs at Cape San Lucas. Nine of the 21 species from the Gulf of California also occur in the Panamic fauna. One deep-water cosmopolitan species, Desmophyllum crista-galli Milne Edwards and Haime, is found off both San Diego and Panama. Tables indicate, insofar as possible, the bathymetric and thermal distribution of the species. Eight genera and 17 species belong to the reef-coral group, but the only reefs known in the area are monospecific, being composed of either Pocillopora robusta Verrill or Porites californica Verrill. The generic affinities of the fauna are preponderantly Indo-Pacific. A chart shows the coral genera known from the Tertiary of California, Oregon, and Washington. The available Pacific Coast data indicate that the Atlantic and Pacific coral faunas were differentiated some time in the Miocene, which agrees with Vaughan’s previous conclusion based on Caribbean coral faunas. The distribution of corals in the late Cenozoic of the Gulf of California area is also recorded and discussed. It is concluded that the generic relationships of the Imperial formation corals of southeastern California are not necessarily entirely with the Caribbean faunas, inasmuch as four of the six genera occur in earlier Pacific Coast Tertiary faunas. During part of the Pleistocene some reef-coral genera are found farther north in the Gulf of California than their present northern limit of distribution, indicating a warmer climate then.