518 E. I. WERBER 



The microscopic examination of sections revealed on the left 

 side (right side in the illustration, fig. 77) a practically normal 

 eye. On the right side in the place of the eye is seen the mouth 

 cavity. The ophthalmoblastic material which was to form the 

 right eye has been largely destroyed and only a small fragment 

 of it has been left, which has developed into an optic cup- 

 fragment, seen enclosed in the cranial cavity at the base of the 

 brain. This fragment of the optic cup shows all layers, includ- 

 ing the fibrous layer, of the retina well differentiated. 



The brain is bilobed and no abnormalities can be found in it 

 excepting its oblique position in the head with regard to the 

 main body axis. This is either secondary to or syngenetic with 

 the herterotopia of the mouth, which in turn is due to the destruc- 

 tion of the ophthalmoblastic material of one side. The elimina- 

 tion of the latter has allowed the mouth to expand in the direc- 

 tion of least resistance so far, as to occupy the exact position of 

 the lacking eye, while the excessive expansion of the mouth on 

 this side may have caused distortion of the brain in its relation 

 to the body axis. 



Very interesting conditions are found also in the embryo, a 

 dorsal view of which is presented in figure 14 (p. 490). 



The left eye is lacking and there is a very distinct invagina- 

 tion where the eye should be. On examination of the ventral 

 side the mouth could be seen to be of a shape approaching the 

 'proboscis' type. Its position was very near to what was to 

 be the place of the lacking eye. No other abnormalities could 

 be observed in the embryo in toto. 



Microscopic examination of sections reveals a normal olfac- 

 tory pit and normal eye on the right side. In sections through 

 the posterior third of the eye (fig. 78) the mouth appears almost 

 exactly in what was to be the place of the eye. An unusually 

 small left olfactory pit comes into view at this level and a 

 minute 'independent' lens is noted on the maxilla. Two more 

 minute lenses are found on sections still more posteriorly (fig. 

 79). The origin of these lenses on the eyeless side I am in- 

 clined to consider as due to contact of remnants of the destroyed 

 ophthalmoblastic material of this side with the ectodermal 

 epithelium. 



