356 E. I. WERBER 



A very remarkable feature is presented by this optic cup in the 

 twenty-eighth and twenty-ninth sections (fig. 5). Here a small 

 body is found which has the same staining reaction as the lens 

 of this eye and all the lentoids observed in the embryo. It is 

 situated in proximity to the layer of rods and cones and is sur- 

 rounded by practically all other layers of the retina. On first 

 examination the impression was gained that we are here dealing 

 with an artifact, namely a lens fragment carried in by the knife 

 during sectioning. This suspicion, however, proved to be un- 

 founded for the following reasons. First, the structure appears 

 in two sections in exactly the same position, and it is larger in 

 the second section containing it, the part observed in the pre- 

 ceding section being its tip. Secondly, if it were an artifact, 

 it would necessarily have to overlie a corresponding part of the 

 retina, which is not the case, for on deep focusing on the first 

 part (contained in section 28) nothing can be observed below the 

 section of this structure, while a deep focus on its second part 

 (section 29) discloses only pigment cells, with which it is sur- 

 rounded on all sides but one. The morphogenesis of this len- 

 toid is, of course, uncertain. But it seems probable that we 

 are here dealing with a 'retinal lentoid' such as was in many in- 

 stances observed by Fischel ('02) after mechanical injury of the 

 retina. In this case our retinal lentoid would have to be re- 

 garded as a case of embryonic heteromorphosis induced by chemi- 

 cal alteration of the environment. 



More evidence for blastolysis is presented by the dissociated 

 epidermis,^ and the unusually distorted shape of the brain of 

 this embryo as well as by the significant fact that in posterior 

 sections of the eyes there appear dorsally from the latter two 

 more rudimentary optic cups, the retina of which (rods and 

 cones) while not fully differentiated, yet is clearly discernible. 

 These optic cups have not been pushed out by the brain, but 

 each one forms a part of its dorso-lateral wall almost exactly 

 where one would expect the optic lobes, which latter, owing to 

 the distortions of the brain, can nowhere be recognized. This 



* The embryo was alive when fixed. All my observations on teratological 

 material were made only on embryos alive at the time of fixation. 



