456 



Nachdruck verboten. 



An open Cleft in the embryonic Eye of a Cüick of eight Days. 



By Otto Landman, Toledo 0., U. S. A. 

 With 5 Figures. 



The eye was that of a chick's embryo which was hatched out 

 with some others, thus allowing a comparison to be made between the 

 abnormal and normal of precisely the same age, eight days and one 

 hour. They were hatched at 40° C and fixed in Zenker's solution. 

 The head and eyes seemed a trifle smaller than the normal ones. 



There was a large cleft of each iris, directed downward, which 

 could be seen with the naked eye. 



The eyes were cut in sections, of 10 microns, horizontal to the 

 plane of the cornea and thus as nearly as possible at right angles to 

 the foetal cleft. 



Both eyes were alike and consequently a description of the one 

 applies to the other. 



The lens was normal in every respect. 



The following abnormalities were found : A complete cleft extend- 

 ing from the edge of the pupil to the region of the optic nerve. 



An inversion of the lips of the foetal cleft throughout its entire 

 extent except in the iris. 



Pigment extending unto the inner layer of the secondary optic cup. 



Absence of the ciliary processes. 



Absence of the pecten. 

 The cleft in the iris occupied about one sixth of its whole ex- 

 panse and showed the following peculiarity. The one limb of the 

 iris-cleft was almost vertical to the limbus of the cornea, whereas the 

 other limb came from the edge of the pupil downwards, towards its 

 juncture with the first limb obliquely in a line curved downwards and 

 outwards forming almost a right angle with the first limb. The cleft 

 extended to the root of the iris. From this point the cleft is open 

 almost to the opticus. At the root of the iris the lips of the cleft 



