352 MERISTIC VARIATION. [part i. 



Fackenheim, I.e., p. 359, fig. iv.). Thus do the two conditions pass 

 into each other, though some cases are clearly cases of duplicity and 

 some are clearly cases of extra digit in Succession 1 . 



I know no case of unmistakeable duplicity in any digit but pollex or 

 hallux ; but no doubt a good many cases of extra digit arising from the 

 minimus may be of this nature (e. g. Annandale, PI. in., fig. 28), though 

 it is more likely that the extra digit is in Succession. 



In digits other than I or V the only case of possible duplicity known 

 to me as occurring in a limb not exhibiting one of the complex conditions 

 of polydactylism, are those of Streng (Vierteljahrsschrift f. prakt. Heilk., 

 xlix. 1856, p. 178; original not seen by me; quoted by Gruber, 

 p. 476), being a case apparently of double medius on one metacarpal ; 

 and of Dusseau, Cat. Mus. Vrolik, No. 518, two terminal phalanges on 

 right medius (together with double thumb ; six fingers on left hand 

 and peripheral duplicity of hallux in each foot). Accompanied by 

 numerical Variation in other parts of the digital series such cases 

 of duplicity are known in a few other cases. 



(3) Combinations of the foregoing. 



Limbs not rarely present the forms of polydactylism already named 

 in combination. Such combination may be found in the same limb, or 

 one or more limbs may present one form, while another form may be 

 found in the other limb or limbs. Of these combinations the following- 

 three cases will be sufficient illustration. 



Case of double hallux on each foot, and rudimentary digit attached by 

 peduncle to the minimus of each hand. 



516. A female member of a polydactyle family [particulars giveu] had au abortive 

 supernumerary finger attached by a peduncle to the little finger of each hand. In 

 the feet the two great toes were each partially double. In the left great toe the 

 individual phalanges could be felt and there were two nails. In the great toe 

 of the right foot the adjacent sets of phalanges were inseparably united by their 

 lateral borders, forming one bone, which was correspondingly broadened. There 

 was only one nail which was notched in the middle of its free border. Muir, J. 

 S., Glasgow Med. Jour., 1884, N. S. xxi. p. 420, Plate. 



Case of each extremity with double pollex or hallux and rudimentary 

 digit attached to minimus. 



517. Female infant having thumb of each hand double, the two sets of bones lying in 

 the same skin and connective tissue. In the right hand the nails and phalanges of 

 each were quite distinct, but it was not certain whether the metacarpals were 

 separate or not. In the left hand the nails were not completely separate and the 

 phalanges of the two thumbs were less distinctly separate. To the first phalanx of 

 the little finger of each hand was appended a rudimentary bud-like finger, hanging 

 by a peduncle. 



The feet resembled the hands. From the inner border of the metatarsal of each 

 great toe there proceeded a well-formed thumb-like toe with two phalanges. This 

 toe was set at right angles to the great toe and could be flexed and to some extent 

 opposed. On the external border of the right foot there was a small extra little toe 

 hanging by a peduncle from the metacarpal V. In the left foot the supernumerary 

 little toe was bound up with the normal little toe for its whole length. Hagenbach, 

 E., Jahrb.f. Kinderheilk., xiv. 1879, p. 234, figs. [Cp. No. 514.] 



1 Compare with the largely similar series of phenomena seen in the foot of the 

 Dorking fowl (v. infra). But in it if the two hallucal digits are not a true pair it is 

 most commonly the inner that is the largest, conversely, to the general rule in 

 the extra digits arising from the pollex in Man. 



