1900.
12.

The Sacral Spot in Maya Indians.Science.

1903.
Naturally, in a work of such extent we have been under obligation to many parties.

It is impossible to acknowledge, in detail, such obligations.

We must, however, express our indebtedness, for assistance rendered, to the Mexican Central Railroad, the Mexican Railway, the Mexican National Railroad, the Tehuantepec Railroad, the Mexican Southern Railroad, and the Interoceanic Railroad; also to the Ward Line of steamers.