PHYSIOLOGICAL DOMINANCE 



107 



correspond to these different types of head^ and are 

 undoubtedly the fundamental factors in determining 

 general form and localization of the parts in the head. 



J « 



('Mi: 



cic 



(jno 



:m) 



C10 



TV 



54^ 



:P4) CMJ 



^j^r 



54^ 



55^ 



55 B 



56^ 



56^ 



Figs. 54-56. — DifEerent results of reconstitution in Planaria 

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

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

 forms; Fig. 56^, B, anophthalmia 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 



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

 tophthalmic and Teratomorphic Forms of Planaria dorotocephala," 

 Biol. Bull., XXII, 191 1. 



