382 



M ERISTIC VARIATION. 



[PART i. 



had does such ;i dL'it- ^roup itself into the Symmetry of the normal 

 maiius : but it stands apart, or is bent or adducted behind the other 

 diLrit-, having a ho. .f \vhidi is irregularly pyramidal, curving in neither 

 direction especially. Such a digit has generally three phalanges, and 

 is of about thf size of digit II, though not rarely it is large in size 

 approaching more nearly to III than to II (as Coll. Surg. Jfus., Ter. 

 Ser., L".'7>. 



extra diyits internal to digit II, 



.")71. This condit ion is not less common than the last. The two extra 

 dibits art- Ix.rne cither by two separate extra carpal bones (Fig. 119, c 1 , 

 c'), "i- by (tin- carpal imperfectly divided (ERCOLANI, 1. c., PI. i., Jig. 6); 

 or i lie metacarpals of the extra digits simply articulate against the 

 carpn -metacar -pal joint of II (as in a specimen in my own possession). 

 The extra dibits may be double throughout, or the two may be com- 

 pounded in their proximal parts (ERCOLANI, 1. c., PL i., fig. 5; also case 

 in < >xt'onl Mus. 1 , 150G, , in which the two extra digits were ill-formed 

 and of uiH-ijual size, having a common metacarpal). Fig. 119 shews 

 Mich a pair of extra dibits in their most complete form. The central 

 part of the metacarpal of II has either never ossified or has been 

 absorbed. As bearing on the question of the relations of parts in 

 MerUtic Hep, <t it ion tin- fact of most importance is the circumstance 

 that the digits III and IV retain their normal Symmetry, but the two 



KM. ll'.i. T.rft manuR of a Pip, No. 571. 



I. View from in front. II. View from inside to shew the convergence of 

 <l } and i/- towards each other. 



(/', (/-, two extra digits placed internally, c 1 , c a , two extra carpal bones with 

 \vhidi they articulate, sc, scaphoid. In, lunar, cit, cuneiform, t, trapezoid. 

 in. magnum, n, unciforni. d 3 rf 6 , the digits II, III, IV, V. 



1 For note of this specimen I am indebted to Mr W. H. Benham. 



