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S. R. DETWILER 



April 12. Two small gills developing anterior to limb. Limb abor- 

 tive and is rotated dorsally. 



April 20. Posterior (second) gill fused along anterior border of 

 atrophic limb. First gill very small. 



April 29. Animal preserved (fig. 27). 



Section of the above case shows the presence of several abortive and 

 abnormally developed branchial bars. There is a small limb girdle, 

 the glenoid cavity of which is deeply situated. Only the distal portion 

 of the arm is free from the body. The appendage lacks muscular 

 differentiation. The ectoderm of the fused external gill (fig. 27) is 



EG 2 



Fig. 27 Dorsal view of case AA2S65. Right anterior limb transplanted into 

 gill region as under conditions described in table 1 B. The limb (L) is abortive. 

 Two abortive gills are seen anterior to the limb. The second {EG2) is fused along 

 the radial border of the limb. Animal preserved twenty-six days after the 

 operation. X 10. 



continuous with that covering the extremity. No vascular elements 

 are differentiated. 



Case AA^Sei. April 4, 1920. Operation. Experimental conditions 

 as in case AA2S27. 



April 5. Completely healed. 



April 10. Limb bud developing with normal orientation. No 

 evidence of developing gills. 



April 15. Limb points dorsally and the proximal part is fused to 

 side of body wall. Gill ectoderm fuses along dorsum of the limb. Very 

 small, abortive gills developing ventral to the typical gill region. 



April 20. Distal portion of Hmb club-shaped. Digits fail to develop. 

 Gill ectoderm is connected with hmb along its dorsomesial border. 

 Small spur developed on lateral border of arm. 



