PREFACE. 



The present publication was prepared by request of Henry Fairfield 

 Osborn, President of the American Museum of Natural History, to whom 

 the author is indebted for courtesies extending over many years of the most 

 pleasant official relationship. 



It is a pleasure, realized by few, to be able to supervise the publication 

 of a list of one's own technical papers, extending over more than half a 

 century, and the opportunity for it was duly welcomed. 



The biographical sketch, preceding the list of papers, however, was 

 written with great reluctance and with many misgivings, as being, in the 

 author's opinion, inopportune in the present connection. If such notes 

 are worthy of record, it seems more fitting that their publication should be 

 posthumous. Their present appearance is due to solicitations difficult to 

 disregard. 



J. A. Allen. 



August 20, 1916. 



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