UC San Diego Library – Scripps Digital Collection

This key treats of the families of marine fishes that are represented by species that have been found within a depth of 100 fathoms on the western coast of the United States, exclusive of Alaska. The characters here used do not define the families as a whole; but they serve as a means of identification of the families as restricted by the fishes that happen to occur within the limits of the locality here considered. For instance, "Body tapering backwards to a point" is not a character that defines the family Soleidae, but it is a character of the only member of that family that is found on our coast. Hence this key is in most cases useless for the identification of these same families as represented in other localities.