C. M. CHILD AND E. V. M. McKIE. 



the normal anima! (Fig. 4). The ganglionic mass itself is some- 

 what irregular in form and shows no trace of a division into 

 symmetrical right and left portions. 



Figure 13 shows the condition of the ganglia six sections (sixty 

 micra) posterior to the eye. Here the fiber tracts show indica- 

 tions of a symmetrical arrangement, hut this arrangement is 

 widely different trom the normal. Three sections farther pos- 

 teriorly the fiber tracts are still more broken up, as shown in 

 Fig. 14. The level of this section is approximately the posterior 

 end of the anterior new tissue of the regenerated region. Fig. 15 

 shows a section sixty micra posterior to the level of Fig. 14, /. e., 

 in the old tissue: here tin- nervous system appears in the usual 

 form of two ganglionic ventral cords, which, however, are much 

 less widely separated than in the- normal animal at this level. 



2. The animal sectioned is shown in Fig. 16. The head is 

 much like that in Fig. 10, but the auricles are somewhat closer 

 together. A single median eye with a rather large pigment spot 

 is present. 



Figures 17 and 18 show sections of the head. Fig. 17 is a 





16 



18 



Fics. 16-18. 



section a short distance anterior to the eyes, about the posterior 

 fourth of the preocular region. Fig. iX shows the level of tin- 

 eyes . The single pigment cup appears in the liguiv io open 

 ventrally, but the opening is actually antero-ventr.il in direction. 

 The ganglionic mass is distinctly double, /. c., more- like the 



