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Mary Isahelle Steele 



ating tissue and the condition of the remaining old parts. Sections 

 were sometimes depigmented on the shde. For this Mayer's 

 chlorine method was used. 



Table I gives in brief a record of the individuals operated upon, 

 the character of the operation and the end results. 



Ill The Normal Adult Eye 



Before taking up the discussion of the regeneration of the eye 

 it will be perhaps well to give a brief description of the structure of 



Text Fig. I The lines, a-h, a-c, a-d, a-e, a-f, a-g and a-h represent approximately the different 

 levels at which a part or whole of the eye has been removed. When the cut was at level as low as a-e 

 a part of the optic ganglion was usually involved. In Palaemonetes the eye never regenerated when the 

 cut came as low as the level a-e. Hermit crabs may regenerate an eye from the level a-j and a hetero. 

 morphic appendage from the level a-h. 



the normal eye. The nature and extent of the operations and the 

 subsequent changes in the eyes will then be more easily under- 

 stood. The eye of Palaemonetes has been concisely described by 

 Parker ('97) and the following description is adapted from his. 

 It is to be noted that the eye structure of the three forms experi- 

 mented upon is practically the same. 



