FOSSIL ANTHROPOIDS OF THE YALE-CAMBRIDGE 
INDIA EXPEDITION OF 1935 
INTRODUCTION 
The Yale-Cambridge India Expedition of 1935, under the direction of 
Dr. H. de Terra, secured from several localities in the Siwalik hills a small 
but valuable collection of fossil ape teeth and parts of jaws; these prove 
to be of considerable importance, especially when added to the collections 
of the Yale North India Expedition of 1931-1933. Through the kindness 
of the Director of the Geological Survey of India, a small collection of 
Siwalik anthropoid teeth in the Indian Museum, Calcutta, has been loaned 
to us for study and description. Accurate casts of the type specimens of 
Lydekker’s and Pilgrim’s species were supplied by the same institution, 
and we are also indebted to the Prince of Wales College Museum at 
Jammu for the loan of the third lower molar described below (p. 18). 
At the Peabody Museum, Yale University, the junior author was assisted 
in the preparation of the photographic negatives of plates 1, 2 figures 1-3, 
and 3 figures 1-7 by Mr. F. C. Herpich, who in addition kindly proffered 
the use of his personal equipment. The remaining figures of plates 2 and 38, 
together with plates 4-8, were made from enlarged photographs by Mr. 
Julius Kirschner, of the American Museum. We are indebted to Dr. J. C. 
Merriam and Dr. H. de Terra for the opportunity of studying and describing 
the present material. 
Up to the present time the number of supposed genera and species of 
fossil apes from India has been increasing with every new collection, but, 
notwithstanding our several previous studies, the interrelationships of 
these forms have for the most part been pretty dubious. It was apparent 
that, taking them as a whole, the range of differences in size, form, and 
details of molar patterns was great, and that in these scattered fragments 
there is evidence of a wide genetic radiation of the anthropoids in the 
region of what is now the Siwaliks. All the numerous species described by 
previous authors (Lydekker, Pilgrim, Brown, Gregory and Hellman, Lewis) 
rested on parts of either the upper or the lower jaw and teeth, and in no case 
has the holotype included definitely associated upper and lower teeth. The 
same is also true of the European species of Dryomthecus and allied genera. 
It was our hope that the new collections would enable us to make at least a 
beginning in correlating the upper with the lower teeth and in reducing some 
of the “species” to the rank of synonyms. Fortunately they have indeed 
made possible some progress in this direction and at the same time have 
supplied evidence relating to the phylogenetic sequence of certain species. 
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