chap, xiii.] digits: cat. 315 



indicates that the digit to which it is assigned has the tarsal or carpal relations of 

 the digit so numbered in the normal. For brevity each is described as a right foot. 



I. The normal, consisting of four three-phalanged digits, each 

 retracting its claw to the external, viz. right side, and a rudimentary 

 hallux with no claw. In this foot therefore the digits enumerated 

 from the external side are 



Eight. Eight. Eight. Eight. Eudiment. 



V IV III II I 



II. Five digits, each with three phalanges. Of these the 

 minimus and annularis borne by a normal cuboid are normal and 

 are formed as right digits. The medius is borne by a normal ecto- 

 cuneiform and is also a true right digit. Internal to this is a full- 

 sized digit having the relations of an index and borne by a bone 

 placed as a middle cuneiform. But the claw of this digit cannot 

 be retracted to the external side of the limb, for the second 

 phalanx is not excavated on this side. There is on the contrary a 

 slight excavation on the internal side of the second phalanx, but 

 this is very incomplete and the claw cannot be fully retracted, 

 being in fact almost upon the middle line of the digit when bent 

 back. This digit is thus intermediate between a right and a left. 

 Nevertheless it is truly the index of this right foot, for it has the 

 tarsal relations of an index. 



Internal to this digit is another, which by all rules of homology 

 should be the hallux, but it has three phalanges and is fashioned 

 as a left digit, retracting its claw to the left (internal) side of the 

 digit. This digit (Fig. 85, II, d l ) is borne jointly by two cuneiforms, 

 c 1 and c 2 , as shewn in the figure. There is thus one cuneiform 

 more than there is in the normal. In this foot therefore the digits 

 enumerated from the external side are as follows : — 



Eight. Eight. Eight. Indifferent. Left. 



V IV III II I 



Such a specimen is No. 472, right pes. 



Between this state and the normal I have as yet met no inter- 

 mediate. It might perhaps have been expected that a foot having 

 four three-phalanged digits and a hallux with two phalanges would 

 be a common form of variation. Such a condition has not however 

 been seen, so far as I know. 



III. The foot shewn in Fig. 85, 1 exemplifies the next condition. 

 In it the three external digits, which are structurally the minimus, 

 annularis and medius of a normal foot are normal in form, position 

 and manner of articulation with the tarsus. Internal to the 

 medius are three digits, of which the innermost has two phalanges 

 (Fig. 85, I, d 1 ) and a claw which cannot be retracted, like the 

 pollex of the normal fore foot. The other digits, d 3 and d\ are 

 fashioned as left digits, retracting their claws to the internal or 

 left side of the limb. It will be seen that of them d 3 has the 



