235] 47 



Fig. 26a. Section through regenerating eye. Cornea had been removed 

 24 days. A remnant of old crystalline cones shown at cr. 

 Degenerating optic ganglion (gl) on right side. Regenerat- 

 ing muscle fibers extending to top of eye. 



PLATE 4 



Fig. 26. Eye from which almost entire cornea was removed Apr. 9. 

 Moulted and was killed, May 3. 



Fig. 27. Entire right eye removed. Flagella (««) appeared in three 

 months, after crayfish had moulted twice. 



Fig. 28. Normal eye and regenerated growth from a crayfish that had 

 had entire eye removed four months before. No moult had 

 taken place. 



Fig. 29. Normal eve and regenerated growth from a crayfish whose eye 

 was removed three months before, at end of which time a 

 moult took place. 



Fig. 30. Stump of old eye-stalk and regenerated growth that developed 

 between May 9, the date of removal of the eye, and Aug. 20 

 when individual died. It had moulted twice in the interval. 



Fig. 31. Side view of anterior portion of crayfish, rostrum dissected 

 away. This structure developed between June 9 and Aug 20. 

 A moult occurred Aug 20. 



Fig. 32. Another crayfish, shown as in Fig. 31, except rostrum has not 

 been removed. 



Fig. 33. The same as Fig. 31, except that in this specimen left eye in- 

 state of right had been removed, and the regenerated structure 

 is composed of a greater number of segments. Regeneration 

 shown has taken place in two months, one moult having oc- 

 curred. 



Fig. 34. Similar to the preceding. 



Fig. 35. Normal eye and regenerating eye six weeks after removal of 

 entire cornea, one moult having taken place. 



Fig. 41, Muscle fibers taken from a, Fig. 26a. 



