46 [234 



Fig. 19. Leg regenerating from distal end of 3rd joint. Regenerated 



portion 3 days old. 

 Fig. 20. Double chela. Meros branched. 



Fig. 38. Hypodermis from end of developing chela, 5 days old. 

 Fig. 39. Developing muscle fibers from central portion of regenerating 



chela, bud 5 days old. 

 Fig. 40. Developing muscle fibers from chela bud older than shown in 



Fig. 39, but not yet constricted into segments. 



PLATE 2 



Cast-off shell of crayfish, indicating the number of appendages 



that had been broken off. 



Crayfish that has just moulted from shell shown in Fig. 5. 



Left chela broken off in moulting. 



Cast off shell of crayfish showing visible regeneration before 



a moult. 



Crayfish that has moulted from shell shown in Fig. 7. 



Developing muscular tissue from region e (Fig. 11). Fibers 



very loose and granular with large, deeply staining nuclei. 

 Fig. 13. Developing muscular tissue from region a (Fig. 11). Two 



bands consisting of two and four fibers respectively, separated 



by a broad granular space. 

 Fig. 36. Section of regenerating eye shown in Fig. 35. Specimen 



killed just after a moult. 

 Fig. 37- Section of same eye as Fig. 36, but more eccentric. 



PLATE 3 



Fig. 21. Regenerating eye. Corneal portion had been removed 44 

 days before. Lamellae of new cuticle very loose and very 

 irregularly developed — extends from a to b. 



Fig. 22. Regenerating eye. Corneal portion had been removed 33 

 days before. Outline of regenerated part very irregular, due 

 to unequal development of connective tissue beneath newly 

 formed cuticle. ba. probably bacteria that have become 

 massed over the irregular surface ot the new cuticle. 



Fig. 23. Cuticular portion of regenerating eye from which one side 

 of cornea had been removed 10 days before. At upper left 

 hand portion of figure the remainder of old corneal facets are 

 being thrown off. The hypodermis is a continuous, wel 

 defined structure beneath the whole cuticle. ' 



Fig. 24. Section of regenerating eye, corneal portion removed 44 days 

 before. Section taken eccentrically. The old cuticle covers 

 most of the surface, the new cuticle developing beneath. No 

 well defined hypodermis. 



Fig. 25. Section from same eye as Fig. 24, but less eccentrically taken. 

 New cuticle much better developed in this region; large space 

 between new and old cuticle. 



