chap, xiii.] ONE DIGIT STANDING FOR TWO. 



359 



Upon the morphological questions arising out of these facts comment 

 will be made when the whole subject of numerical Variation of digits 

 is discussed. 



Representation of digits II and III of the pes by one digit. 



Man having four digits in the right foot as shewn in Fig. 105. The calcaneum, 

 astragalus, navicular, first (internal) cuneiform and cuboid were normal. The 

 navicular had on its peripheral surface three facets as usual. The second and third 

 cuneiforms were completely united to form one bone which bore no traces of its 

 double nature as shewn in the figure (c 2 + c 3 ). The peripheral surfaces of both form 

 one plane. Taking the four digits in order, the minimus has its normal form and 

 tarsal relations. The digit next to it has the normal form and relations of a digit IV. 



Fig. 105. Bones of the right foot of No. 529. I, hallux. 11 + III, digit 

 apparently representing index and medius. IV, annularis. V, minimus, a, astra- 

 galus, sc, navicular, cb, cuboid, e\ internal cuneiform. c 2 + c 3 , bone apparently 

 representing the middle and external cuneiforms. (After Gruber.) 



Internal to this is a metatarsal of abnormal thickness articulating with the single 

 bone presumably representing the external and middle cuneiforms. This metatar- 

 sus presented no trace of duplicity. It bore a digit of three phalanges of more than 

 normal thickness but otherwise normal. The hallux was normal, having two pha- 

 langes. Each of the other digits had three phalanges, but the 2nd and 3rd phalanges 

 of the minimus were ankylosed. 



Of the muscles, the transversalis pedis, one of the lumbricales, one of the inter - 

 ossei dorsales and one of the interossei plantares were absent. The extensor and 

 flexor longus each had three tendons. [Detailed description of bones and soft parts 

 given.] Gruber, W., Virch. Arch. f. path. Anat. u. Phys., 1869, xlvii. p. 304, 

 PI. VIII. 



Single digit articulating with the cuboid [probably a case of representation of 

 digits IV and V by one digit]. 



Man having four digits on the left foot as follows. The foot is well formed. 

 The digits I, II and III are normal and have normal tarsal relations. The fourth 

 digit has a well-formed metatarsal and three phalanges. The bones are perhaps 

 rather more robust than those of a normal fifth digit, but the metatarsal has the 

 normal tuberosity at the base strongly developed. This metatarsal articulates with 

 a cuboid of somewhat reduced size having only one articular facet on its peripheral 

 surface. The other parts were all normal, and even in the muscular system only a 

 trifling abnormality was found. Parents normal. Steinthal, C. F., Virch. Arch, 

 f. path. Anat. u. Phys., 1887, cix. p. 347. 



