collections were still undergoing preparation and the study of the
different groups had just begun.

Although the book has been largely written by the senior author, his
collaborator has contributed six chapters marked with her initials; all the
illustrations are from her photographs and continual use has been made of
her daily journals; she has, moreover, materially assisted in reference
work and in numerous other ways.

The information concerning the relationships and distribution of the native
tribes of Yün-nan is largely drawn from the excellent reference work by
Major H.R. Davies and we have followed his spelling of Chinese names.

Parts of the book have been published as separate articles in the _American
Museum Journal, Harper's Magazine_, and _Asia_ and to the editors of the
above publications our acknowledgments are due.

That the Expedition obtained a very large and representative collection of
small mammals is owing in a great measure to the efforts of Mr. Edmund
Heller, our companion in the field. He worked tirelessly in the care and
preservation of the specimens, and the fact that they reached New York in
excellent condition is, in itself, the best testimony to the skill and
thoroughness with which they were prepared.

Our Chinese interpreter, Wu Hung-tao, contributed largely to the success of
the Expedition. His faithful and enthusiastic devotion to our interests and
his tact and resourcefulness under trying circumstances won our lasting
gratitude and affectionate regard.

The nineteen months during which we were in Asia are among