[Introduction]

Many new collections have been added to the holdings of the Allan Hancock Foundation since the onuphids were first published (Hartman, 1944). As a result of the present study, the number of known onuphids from the coast of western Mexico is now 42, of which all but nine are represented in the present materials. Six of the nine are deep water forms described by Chamberlin (1919), taken by the USS ALBATROSS expedition of 1891 from deep areas in the Gulf of California and offshore; these areas have not been re-explored.

The best represented genera in Mexico are Onuphis with 16 species of which 10 are present in the material, Nothria with 11 species all but one of which are present, and Diopatra with eight species all present in the material. Hyalinoecia is represented by four species of which two are present, Rhamphobrachium by two and Paronuphis by one species.

Most of the collections studied were taken by the VELERO III and VELERO IV of the Allan Hancock Foundation. A complete list of stations to 1502-42 is found in Fraser (1943). Data for stations of the VELERO IV in western Mexico from 1688-49 to 7358-61 and separate lists for other collections in which onuphids have been found are given at the end of this report. All material of onuphids from western Mexico in the Allan Hancock Foundation were studied; the lists of new records include only those collections that were not reported on by Hartman (1944). The material is deposited in the collections of the Allan Hancock Foundation, University of Southern California, Los Angeles.

I am grateful to the Allan Hancock Foundation for making the collections available to me, and for material assistance. The work was supported by the National Science Foundation Grant no. B5-1780 to the Allan Hancock Foundation. Drs. Olga Hartman and Rüssel L. Zimmer gave me much valuable advice and Drs. Hartman and J. Savage critically read the manuscript. The results of this study will be used as the basis for a Ph. D. thesis at the University of Southern California.