PHYSIOLOGICAL DOMINANCE 



107 



correspond to these different types of head 1 and are 

 undoubtedly the fundamental factors in determining 

 general form and localization of the parts in the head. 



on? 





545 



V 



55 B 



FIGS. 54-56. Different results of reconstitution in Planaria 

 dorotocephala: Fig. 54_4, teratophthalmic animal; Fig. 54^, different 

 forms of eyes in teratophthalmic animals; Fig. 55^!, B, teratomorphic 

 forms; Fig. 56/1, B, anophthalmic forms. 



As a matter of fact, these different forms are a more or 

 less arbitrary grouping of what is actually a graded series 

 of forms from the normal head at one extreme to the 



1 See Child and McKie, "The Central Nervous System in Tera- 

 tophthalmic and Teratomorphic Forms of Planaria dorotocephala," 

 Biol. Bull., XXII, 191 1. 



