252 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
the sixth, or supernumerary, digit in the right hand, leading us to sup- 
pose this to be the true minimus. But in the deft 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 the two digits produced may develop into an 
Fic. A.— Bones of right hand of man, showing duplicated thumb. 14, 1, pollices; 
cun., cuneiform ; l/un., lunar; os mag., os magnum; ¢rz., trapezium; trz’., accessory trape- 
zium; trzd., trapezoid; scph., scaphoid; scph’., scph’’., accessory scaphoids; wn., 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 
ss 
