From the introductory: Field of Enquiry. The two great cultures of antiquity that flourished, the one upon the Mexican Plateau as a centre of distribution and the other in Central America, distinguished in modern times under the names Aztec or Mexican and Maya or Central American, are related to each other in such a way that, although the distinction between them is clear and free from all confusion, yet it is impossible to take a comprehensive survey of either without considering also the claims of the other. While this observation is perfectly general in its scope, it applies with special force and significance to those forms of expression that have their origin in the artistic impulse and in the speculative faculty. We are not concerned in the present study with questions relating to the source of these affinities, but accepting the fact we are to apply ourselves to a study of actual conditions irrespective of original sources or points of contact. These two great cultures, the Mexican and the Maya, although readily distinguishable not only from each other but from all cultures beside on the Western Hemisphere either by reason of the great advancement made in the arts or else by characteristic modes of thought and expression, have many points of affinity in other regions lying far to the northward and to the south and possessing cultures which in respect of development are peculiarly their own. These affinities are of two kinds: first, imperfectly revealed connections indicating common origin, and second, definite correspondences arising from a borrowing of ideas. The first refer back to a common habitat and primitive condition and the degree of relationship which they imply though it cannot be overlooked, must be regarded as exceedingly remote. The second indicate the intercourse of cultured peoples and imply widespread commercial relations between the aboriginal Americans. The serpent in one form or another, whether as an object of worship, a sacred symbol or a decorative device, is found everywhere on the Western Hemisphere as well as in almost all other parts of the world; but in this connection the position of the animal in. Mexico and Central America is absolutely unique; for nowhere else in the world, if we may judge by traditional and archeological remains, did the serpent and the set of ideas connected therewith assume such supreme importance or attain such an extraordinary development as in the region here defined. Within this region, besides the Mexican and Maya cultures, there is comprised another, closely related to them both and known as the Zapotecan. These three cultures and their corresponding areas constitute our field of enquiry and the special feature to which our investigations have reference may be described as that group of phenomena in which the serpent in one form or another appears as the ruling motive or the means of expression. So persistent and dominant is the serpent motive that a thorough investigation of the subject brings us in contact with the whole body of artistic products.