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bulletin: museum of comparative zoology. 



digit. We can only conclude, then, that digit ii, together with its ac- 

 cessories, has atrophied. This nianus is therefore only pseudo-penta- 

 dactyloiis, and belongs in reality to the hexadactyle abnormalities. This 

 conclusion is made possible only through the completeness of the poly- 

 dactyle series which I have studied, and emphasizes the futility of at- 



n. m. 



IV. 



Fig. T. — Posterior view of left polydactyle manus of the pig, showing innervation. 

 I", I*, supernumerary digits; 1, first brancli of the median nerve, which bifurcates to the 

 extra digits; 2, second branch, a division of which innervates the rudimentary digit ii. 

 i natural size. 



tempting to obtain general results from single cases of polydactylism. 

 Except for the intermediate stages at my disposal, the true significance 

 of the structural conditions shown in Figure 23 could only have been 

 guessed at. 



