406 H. H. NEWMAN 



Class E. Forty of the forty-two individuals are still alive. 

 The two dead ones have evidently succumbed to infection. 

 Six others are evidently dying as indicated by cytolylic action and 

 vacuolization of the yolk near the embryos. The remaining em- 

 bryos belong to two distinct types. Thirty-four show all kinds 

 of eye and other head abnormalities, such as cyclopia, protruding 

 lenses, asymmetrical development of eyes, and rudimentary 

 eyes; in these the rest of the body is fairly well developed, but 

 never differentiated to the point of developing fins. Six indi- 

 viduals show comparatively well-developed heads and eyes, 

 but no trunk differentiation, the body being a minute turned-up 

 stump sticking out from the head. The first lot show much more 

 predominance of the mackerel type of chromatophores than the 

 latter. It seems probable that the mackerel influence has been 

 secondarily suppressed to a large extent in the six individuals 

 with the well-developed heads and reduced bodies. 



Class F. All but three of the eighteen individuals of this class 

 have died and have been removed from time to time, leaving only 

 three that show signs of life. These three individuals are, how- 

 ever, of great interest. One has a pulsating membrane near a 

 flat mass of undifferentiated tissue. This rhythmically contract- 

 ing drum of tissue I interpret as an isolated heart. The other 

 two embryos are examples of isolated eyes. One is certainly 

 an isolated eye, for it has both a pigmented retina and a small 

 lens. The other has a protruding rounded translucent body that 

 I am certain is a lens lying in a flattened cup of tissue which is a 

 very much spread out optic cup. Curiously enough no green 

 chromatophores are to be seen on any of these three embryonic 

 rudiments, although there were undoubtedly some at an earlier 

 period. 



Class G. All individuals now dead and disintegrating. 



All of the individuals in this experiment were preserved for 

 microscopic study and will furnish material for a histological 

 analysis of the hybrid situation. 



No less than seven other experiments performed under condi- 

 tions essentially identical to those employed in this case gave 

 results much like those recorded. In only one other experiment 



