The data on which the following papers are based was secured chiefly during the dredging and trawling expeditions of the Marine Station launch, the Anton Dohrn. The explorations made with the launch began in 1911 and have been continued at irregular intervals to the present. A brief general account of this work was published in the Bulletin of the Academy of Sciences of Southern California, January 1917 and in six Bulletins of the Marine Biological Station of the University of Southern California. <br /><br />The general plan of these studies of Southern California Fishes includes (1) A detailed study of certain groups of our fishes; (2) Studies on certain economic problems; (3) The distribution of the forms known to occur here; (4) The preparation of keys to facilitate the identification of our groups of fishes. <br /><br />For our convenience the keys have been prepared first. Then the general distribution of all the forms known to occur in Southern California has been summarized. Relating to the species taken in our survey the distribution is given somewhat in detail.