320 



C. M. CHILD. 



pharynx whether they arise from the old prepharyngeal, pharyn- 

 geal or postpharyngeal regions. 



The anophthalmic pieces are always more active than the 

 headless pieces described below and their movements are better 

 coordinated; moreover, the motor activity of the anterior out- 

 growth itself shows very clearly that it represents some approach 

 to head formation. 



V 



35 



u 



XT' 



36 



Fir, 5. 35 37. 



6. Headless. (Figs. 35-37.) The headless pieces are dis- 

 tinguished from the anophthalmic by the fact that the new 

 tissue merely fills the contracted wound and does not grow out. 

 According to the degree of contraction of the wound these pieces 

 may appear like Fig. 35 or Fig. 36. Headless pieces which arise 

 from the old prepharyngeal or pharyngeal region always develop 

 a new pharynx (Figs. 35, 36), but these from the postpharyngeal 

 region do not give rise to a pharynx (Fig. 37). 



It will be observed that in the order figured types 2-6 present 

 a gradation from the normal head to the headless condition. 

 The eyes first show irregularities, then appear nearer together 

 and finally in partial or complete fusion in the median line. In 

 the one eyed forms the region between the auricles may be re- 

 duced or absent and the auricles appear in various degrees of 

 approach to each other, or like the eyes partially or wholly 

 united in the median line, and this latter condition is sometimes 

 seen in the anophthalmic forms: in these all possible gradations 

 appear between an outgrowth resembling a head in form to a 

 long slender pointed outgrowth or one which is short and small, 

 and finally this condition passes into the completely headless 

 condition. 



