chap, xiii.] REDUCTION OF DIGITS : MAN. 355 



No. x. p. 474, supposes that this is a case of double-hand, palm to palm (as No. 503), 

 but the original probably means that two adjacent thumbs and two adjacent annu- 

 lares were united, the digits being all in one plane). 



Popham, Dubl. Quart. J. of Med. Sci., xliv. 1867, p. 481. 



Dusseau, Cat. Mus. Vrolik, 1865, p. 457 (very brief, see p. 352). 



Grandelement, Gaz. des hop., 1861, p. 553. 



Lisfranc (see Schm. Jahrb., xn. 1836, p. 263). 



Rorberg, Jour. f. Kinderkr., xxxv. 1860, p. 426. 



Makjolin, Bull. Soc. de Chir., 1866, Ser. 2, vi. p. 505, Jig. (probably case of double- 

 hand). 



Annandale, Dis. of Fingers and Toes, 1865, p. 39 (eight metatarsals on a foot 

 possibly associated with change of Symmetiw). 



Ibid., p. 35, figs. 41 and 49 (pollex with two sets of phalanges but three nails, 

 together with extra digit external to V). Cp. No. 521. 



Heynolp, Virch. Arch., 1878, lxxii. p. 502, PL vn. 



Mason, F., Trans. Path. Soc, 1879, xxx. p. 583 (foot having eight metatarsals 

 and nine digits). 



Melde, R., Anat. Vnters. eines Kindes mit beiders. Defekt d. Tibia u. Poly- 

 dactylie an Hiinden u. Fiissen, Inaug. Diss., Marburg, 1892 (important). 



REDUCTION IN NUMBER OF DIGITS. 



Though in reduction of digits the course of Variation is generally 

 irregular and the result often largely amorphous there are still features 

 in the evidence which may be of use to us, and a few selected cases are 

 of some interest. These features will be spoken of under the three 

 following heads, though for a general view of the subject reference 

 must be made to teratological works. 



(1) Reduction in number of phalanges. 



(2) Syndactylism. 



(3) Ectrodactylism. 



(1) Reduction in number of phalanges. 



As in certain cases of polydactylism it appeared that increase in the 

 number of phalanges in the thumb could be regarded as a step in the 

 direction of increase in the number of digits, so a reduction may be 

 thought to be a step towards diminution in the number of digits. But 

 though many cases of reduction in number of phalanges are recorded, 

 tliere is in them nothing which suggests that they may be fitted into a 

 series of gradual reduction comparable with the series of gradual 

 increase already described. It is indeed chiefly as illustrating the 

 possible completeness and perfection of Variation that these phenomena 

 have a direct bearing on the subject of Meristic Variation. The 

 following case is chosen as being especially regular and symmetrical. 



) 3. , Man having only one phalanx in each hallux, and two in each of the other 

 fingers and toes. The hands were almost exactly alike. The thumb had a 

 short metacarpal £ in. long, and one phalanx (1|- in.), the joint between them 

 being loose as if composed of soft tissue. By the length of the metacarpal (3 in.) 

 the index is longer than the other digits. The next two metacarpals have only half 

 that length. The metacarpal of V is 1\ in. long, but from its obliquity does not 

 project so far as that of IV. The proximal phalanx of the index measures If, medius 

 If, annularis 1, minimus \\. The distal phalanx in index and middle f, ring and 

 little | in. In left hand the distal phalanx of index is proportionally shorter. 

 Except the index all the digits present their usual proportions. The feet are well 

 formed as far as distal ends of metatarsals. The toes are short, pulpy and loosely 

 articulated. Each has two phalanges except the hallux, which has only one. This 

 case was a twin with a normal male. An elder brother and younger sister have the 



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