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bulletin: museum of comparative zoology. 



mal, and its proximal end is relatively large. In digit iir the radial 

 process of the metacarpal bone, a special character of the nianns in recent 

 swine, is greatly reduced, and as a result scarcely touches the trapezoid, 

 Avhile metacarpal ii comes in contact posteriorly with the os magnum. 

 The trochlear ridges of the metacarpals are retained, and the phalanges 

 show no modifications in form. 



n. m. 



Fin. L. — Posterior view of left pnlydactvle nianiis of tlie pij?, sliowinc; iniiorvatioii. 

 n. m., median nerve; 1, branch of median nerve supplviiijj tlie supernumerary digit (i). 

 5 natural size. 



The muscles are not much modified, for the extra digit is small and 

 functionless. In two instances, however, the tendon of the extensor 

 metacarpi ol)liqiuis muscle is inserted intii the proximal end of digit i. 

 This is an interesting condition, as in normal five-toed animals this 

 muscle is likewise always inserted into the metacarpal of the pollex. 



