510 E. I. WERBER 



the embryo was restricted to its most anterior portion. Owing 

 to this lesion resulting from a process of destruction which I term 

 blastolysis, a wedge of blastema (with the sharp point directed 

 posteriorwards) was eliminated, and the subsequent coalescence 

 of the wound surfaces has caused the earliest optic anlagen to 

 fuse. The eliminated wedge-shaped piece of tissue contained ap- 

 parently the future interocular area, much more of the anterior 

 parts of the ophthalmoblastic material of both sides than of 

 their posterior parts, and a part of the potential brain. This 

 would account for the perfect fusion of the anterior part of the 

 eye components, as well as for the incomplete fusion of their 

 posterior parts, of which probably very little had been lost. 

 That the process which caused the injury was apparently one of 

 dissociation and dispersion (blastolysis) would seem to be evi- 

 denced by the retinal fragment, which can only secondarily have 

 come to fuse with the brain, i.e., after the ophthalmoblastic frag- 

 ment which has given rise to it had been dislocated cerebralwards 

 from its natural position. 



d. Cyclopia perfecta. This monstrostity represents a very high 

 degree of ophthalmic malformation. In its morphogenesis it 

 differs from synophthalmic cyclopia, for the perfectly cyclopean 

 eye is genetically a single eye. However, the evidence which I 

 have been able to find, points to the same dynamic process, 

 namely, blastolytic action of the altered environment as the 

 factor responsible for its formation. 



A few examples may now be presented. 



In figure 6 (p. 488) is presented an embryo which is possessed 

 of a single median eye and small defective fins, partly obscured 

 from view by the very large oedematous ear vesicles. The 

 whole body is distended and the tail is finless and club-shaped. 



The examination of the eye discloses a very remarkable con- 

 dition. Already in toto (fig. 6) the eye is seen to be abnormal 

 in shape and in the position of the lens, which is situated postero- 

 laterally, instead of being anteriorly and in the center of the 

 eye. The front of the eye is entirely closed over by the pig- 

 ment layer, so that the condition presented might almost be 

 considered as a rotation of the polar axis of the organ. 



