AN EXPERIMENTAL STUDY OF THE POSITION OF 

 THE OPTIC ANLAGE IN AMBLYSTOMA PUNC- 

 TATUM, WITH A DISCUSSION OF CERTAIN EYE 

 DEFECTS 



CHARLES R. STOCKARD 



Department of Anatomy, Cornell University Medical College, Neiv York City 



NINE FIGURES 



INTRODUCTION 



Numerous investigations have recently been directed towards 

 an analysis of the processes concerned in the development of 

 the vertebrate eye. Both mechanical and chemical methods of 

 experiment have been employed and at the present time most 

 of the results seem open to explanation. Various theories and 

 speculations, however, have been advanced which will probably 

 form a source of contention until the experimental results are 

 better or more uniformly interpreted. 



By way of introduction to the experiments recorded in the 

 present paper and a discussion of their significance, it may be 

 well to outline briefly the status of the main problems concerned. 



The writer has previously recorded the results of experiments 

 bearing upon an analysis of the manner of origin and develop- 

 ment of the optic cup and the optic lens. It was demonstrated 

 that in the- species studied the crystalline lens can arise entirely 

 independent of any influence from other eye parts. It seems also 

 equally clear from the many cases observed that the optic vesicle 

 or cup can at some stage during its development induce the forma- 

 tion of a lens from the ectoderm with which it comes in contact. 



253 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 15, NO. 3 

 NOVEMBER, 1913 



