52 C. M. CHILD AND . V. M. McKIE. 



right and left halves (Fig. 30). This peculiar arrangement con- 

 tinues to about the posterior end of the regenerated region and 

 then changes into the form shown in Fig. 31: posterior to this 

 the two ventral cords appear in the usual form. 



These five cases give some idea of the variations in structure of 

 the eyes and the nervous system in the teratomorphic forms. A 



FIGS. 28-31. 



more extended investigation of these forms will undoubtedly 

 show other variations in structure and examination of anoph- 

 thalmic and headless forms will add still further data of interest. 



V. DISCUSSION. 



In all of the cases described, both the teratophthalmic and 

 the teratomorphic forms, the most conspicuous difference in the 

 nervous system as compared with the normal forms is the more 

 or less complete fusion in the median line of the two portions 

 of the ganglionic mass, or more correctly, their incomplete 

 separation. 



It is evident that to some extent the condition of the eyes or 

 eye is an index of the condition of the nervous system. The 

 parallelism is, however, not complete: in Case I (Figs. 10-15), 

 for example, the nervous system is much more abnormal than 

 in Cases 2 (Figs. 16-18) and 3 (Figs. 19-22), though all three 

 possess a single median eye. 



Moreover, the degree of fusion of the auricles does not corre- 

 spond exactly to the degree of fusion of the ganglia in all cases. 



