Chapter I 

 INTRODUCTION 



Although the ophthalmoscopic and naked- 

 eye appearances of the fundus oculi have been 

 thoroughly described and depicted by other 

 writers in many of the Mammals — espe- 

 cially in Man — yet very little attention has 

 been paid to the remarkable and interesting 

 eyegrounds of the animal that exhibits the 

 highest and most varied types of vision — 

 the Bird. The meagre accounts given by 

 even modern writers of the appearances of 

 the avian fundus are probably due either to 

 their quoting the ill-formed opinions of early 

 observers or to their ignorance of the proper 

 use of the ophthalmoscope; facility in the 

 employment of this instrument is acquired 

 only after long practice, and it is not to be 

 expected that every zoologist can make his 

 own notes of fundus pictures. 



The main purpose of this study is to furnish 

 such a description of the intraocular appear- 

 ances and the methods employed in viewing 

 them as will enable other ophthalmologists 

 and zoologists to further this study by ex- 

 amining the eyegrounds of Birds that come 

 under their observation. 



The eyes of some representative of (prac- 

 tically) all the Orders of Birds and most of 

 their backgrounds have been examined by 

 the writer; and are more or less fully de- 

 scribed and illustrated in this Atlas. More- 

 over, some of the more important species 

 were examined not only ophthalmoscopically 

 before death but macroscopically afterwards. 

 In addition to these methods of investigation 

 extensive microscopic examinations of the 

 tissues were carried on, especially in conjunc- 

 tion with Professor J. R. Slonaker. 



That this research might have a broader and 

 more useful application the writer has also ex- 



amined the ocular fundi of a number of species 

 of other vertebrate orders. A brief compari- 

 son will be made between a few of these find- 

 ings and those discovered in the avian fundi. 

 The writer is much indebted to many 

 colleagues and other friends for assistance 

 in carrying out the present investigations, 

 which he began more than ten years ago. 

 Among these are the officials of the London 

 Zoological Society, Mr. Chas. H. Hicks in 

 particular; Professors James R. Slonaker and 

 Frank W. Weymouth of Stanford University; 

 Mr. C. W. Beebe, of the New York Zoloogical 

 Park; Mr. Cy de Vry of Lincoln Park, Chi- 

 cago, and the officers of the Golden Gate Park, 

 San Francisco, California; and Mr. Arthur 

 W. Head (the well-known artist) who has so 

 ably depicted and reproduced in this work 

 the avian fundi therein described. His thanks 

 are also due to Mr. C. H. Kennedy, now of 

 Cornell University, who has drawn so faith- 

 fully most of the black and white figures in 

 Chapter VII, illustrating the macroscopic 

 findings of preserved specimens. He is also 

 under obligations to Mr. Douglas Fyfe, who 

 made for him a collection of birds' heads in 

 the United States of Colombia; to Lieut.-Col. 

 J. W. Barrett of Melbourne, who performed 

 the same service in Australasia, and to a num- 

 ber of Calif ornians, among them Messrs. Van 

 Rossem, Wright M. Pierce, R. H. Beck, 

 Lieut. Casey Hayes (U. S. Army) and the 

 Managers of the Cawston Ostrich Farm and 

 Bentley Ostrich Farm, who furnished him 

 with abundant material from the Pacific 

 Coast. He also owes his thanks to Professor 

 J. Grinnell for the loan of material from the 

 Museum of Vertebrate Zoology of the Uni- 

 versity of California; to Dr. T. A. Woodruff 



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