252 



BULLETIX: MUSEUM OF COMPAKATIVE ZOOLOGY. 



the sixth, or siipeniunierary, digit in the rir/ht hand, leading us to sup- 

 pose this to be the true minimus. But in the left hand the sixth digit 

 was rudimentary, and the fifth must therefore be taken as the normal 

 minimus. These abnormalities, which occur on the ulnar side of the 

 extremity, may therefore be best explained as due to duplication of the 

 minimus ; either one of tlie two digits produced may develop into an 



III. II. 



Fig. a. — Bones of riglit hand of man, showing duplicated thumb, i", i*", pollices; 

 cun., cuneiform; lun., lunar; os mag., os magnum; trz., trapezium; trz'., accessoiy trape- 

 zium; <rzrf., trapezoid; scph,, scaphoid; scph'., scpk"., accessory scaphoids; «»., unciform. 

 (After Bateson.) 



apparently normal fifth digit. To this class belong the greater number 

 of digital abnormalities in man. 



There are a few cases of polydactylism in man where one extra digit 

 has been interpolated. Bateson regards these cases as of doubtful origin. 



B. Observations. 



Through the kindness of Prof. W. F. Whitney, Curator of the Warren 

 Museum at the Harvard Medical School, I was permitted to study the 

 skeletal parts of twelve polydactyle extremities in man, and to obtain 



