I am especially grateful to Dr. George Vaillant, of the American
Museum of Natural History, who has been my constant mentor
throughout the investigation. In many a conference, he has given
unsparingly of his time and brought the full richness of his experi-
ence in Middle American archeology to bear upon the problems at
hand. Both he and Mr. Clarence Hay have been particularly helpful
in pointing out resemblances between Tres Zapotes figurines and
figyrines -- from the Valley of Mexico and Morelos. Dr. H. J., Spinden,
of the Brooklyn Museum, has also given me the benefit of consultation.

In Mexico, I am greatly indebted to Mr. Ignacio Marquina, of the
Dirección de Monumentos Prehispánicos, not the least of whose services
was that of expediting technicalities connected with getting excava-
tion under way; to Mr. Eduardo Noguera, for his astute observations
on the pottery and the figurines; to Lic. Juan Valenzuela, of the Museo
Nacional, for giving me access to material and unpublished reports of
excavations in the Tuxtla region, and for confirming comparisons
between the pottery of Tres Zapotes and that of Monte Albán; to Mr.
Wilfrido Du Solier, for valuable data on the pottery of El Taján; to
Mr. Miguel Covarrubias, for his kindness in showing us his superb
private collection of archeological specimens, many of them highly
relevant to the present study; and, above all, to Dr. Alfonso Caso,
not only for the generous cooperation received from him in his official
capacity as Director of the Instituto Nacional de Antropología e
Historia, but for his kindness in permitting me to study, under his
supervision, both in his private laboratory and at the Museo Nacional,
the ceramics of Monte Albán. Without this preparation during the
summer of 1937, I should hardly have had the courage to undertake
the present investigation. Special thanks are due, also, to Mr. Ri-
cardo Gutiérrez, of Tres Zapotes and Tlacotalpan, for the way in
which he looked after our material needs and physical comfort while
in camp.

For bibliographic data on the Hueyapam area, I am indebted to
Mr. Arthur E. Gropp, of the Tulane University Institute of Middle
American Research, and for data out of the general archives of the
Mexican nation, I am obliged to Prof. Paul Kirchhoff, of the Depart-
ment of Anthropology in the Escuela de Ciencias Biológicas, Instituto
Politécnico Nacional, Mexico, D. F.

Mr. Charles E. O'Brien, assistant curator of ornithology at the
American Museum of Natural History, was kind enough to undertake
classification of as many of the bird effigies as it was possible to
identify.

For the preparation of the illustrations I am grateful to Mr. E. G.
Cassedy, artist of the Bureau of American Ethnology, and for help

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