346 



MERISTIC VARIATION. 



[part I. 



506. Extra digit arising from one of the phalanges of minimus. 



Axxandale, I.e. ; Otto, Monstr. sexc. Descr., Taf. xxv. fig. 7; Cramer, Wochens. 

 f. d. ges. Heilkunde, 1834, No. 51, p. 809; Gaillard, Gaz. med,, 1862. This form 

 seems to be comparatively scarce. 



507. Extra digit arising from metacarpus or metatarsus of minimus. 



The great majority of cases are of this nature but exhibit many differences of 

 degree. The articulation may be on the side of the metacarpus V (see Morand. 

 Mem. Ac. Sci. Paris, 1770, p. 142, fig. 4; Coll. Surg. Mus., Catal, Teratol. Ser.', 

 1872, No. 308, and numerous other cases), or of the metatarsus V (see Grurer, I. c 

 p. 476, Note 28) but in the pes this is less common. Frequently also the articulation 

 of the extra digit is on the head of the metacarpus V (Gaillard, I. c.) or metatarsus 

 V (Mus. Coll. Surg., Terat. Ser., No. 310). 



In the foregoing cases the extra digit articulates immediately with the side or 

 head of metacarpal or metatarsal, but sometimes in the manus and often in the pes 

 the digit articulates at the end of a branch given off by the metacarpus (Morand. 

 ibid., fig. 3, and numerous other records), or by the metatarsus (Morand, /. c; 

 Struthers, Edin. New Phil. Jour., 1863 (2), p. 89; Meckel, J. F., Handb. d. path. 

 Anat., ii. Abth. 1, p. 36, and many more. 

 5 OS Hylobates leuciscus (Fig. 99) having an extra digit in the left manus arti- 



culating externally with the metacarpus V and in the right manus articulating with 

 a branch from it. Mus. Coll. Surg., Teratol. Ser., No. 307, A. 



Fig. 99. Hylobates leuciscus, No. 508, minimus of right and left manus bearing 

 a supernumerary digit articulating with the metacarpals. 



(From specimen in Coll. Surg. Mus.) 



(b) Complete digit having metacarpus or metatarsus external 



to minimus. 



Extra digits external to the minimus are occasionally complete, 

 having a metacarpal or metatarsal and three phalanges, standing 

 truly in series with the other digits, but to judge from the records 

 this complete form is decidedly rare. In the first of the following 

 examples given it should be noted that the digit standing fifth, 



