(HAP. xiii.] POLYDACTYLE FOOT : MoCOCUS. 343 



respectively, the Y and the IV articulating with the cuboid (<:/,) ,-md 

 the III with an external cuneiform, c 8 , as usual. There is a middle 

 cuneiform, c 5 , bearing a digit, 6, which is almost exactly formed as a II. 

 Internal to this point the parts can only be named with hesitation. 

 The tarsal bone, c 4 , of the distal series internal to c 5 is shaped like 

 another c 5 , but the digit which it bears rather resembles a minimus. 

 This is succeeded by a tarsal bone, c 3 , shaped like the external cunei- 

 form, c 6 , but it bears a digit of the length suited to an annularis. 

 Internal to this are two tarsal bones of the distal row, c 2 and c 1 , which 

 bear three digits, 1, 2, and 3. Of these the most internal is undoubtedly 

 an internal cuneiform ; it bears firstly a slender but otherwise normal 

 hallux with two phalanges, and secondly, it contributes (abnormally for 

 an internal cuneiform) to the articulation of a digit, 2, which is thinner 

 than all the others and resembles rather a minimus than an index. 

 The digit, 2, also articulates with c 2 which chiefly supports the third 

 digit. 



Between the metatarsals of the digits 5 and 6 there is a considerable 

 space, owing to the fact that the head of the metatarsal of 6 is pro- 

 longed upwards like that of a normal metatarsal V. 



In addition to those described are four other tarsal bones : firstly, a 

 calcaneum c, which is rather smaller than that of the normal right 

 leg. It articulates with the cuboid, cb, with the astragalus, A, and 

 with the bone, n 2 . The astragalus is very large in its transverse 

 dimension but its length is less than that of the normal astragalus. 

 Peripherally it bears two bones, firstly, a navicular, n 1 , and secondly, 

 a bone of uncertain homology, marked n 2 in Fig. 96. The navicular 

 articulates with c 1 , c 2 and c 3 , together with the bone n 2 . The latter, n 2 , 

 articulates with c 3 , c 4 , c 5 , c 8 , and also with the cuboid, cb, the astragalus 

 and calcaneum and navicular. From its form and relations it is 

 probably a second navicular. 



The bones of the crus are three. Firstly, a tibia, tib., which is 

 rather thinner than the normal bone and is somewhat bowed inwards. 

 Passing as a chord to the curve of the tibia there is a thin bone, Jib 1 , 

 which is tendinous in its upper part. External to this, articulating 

 with the external condyle of the femur there is a third bone, Jib 2 , 

 which has nearly the form and proportions of a normal fibula. All 

 three bones articulate with the large astragalus. 



There is a small patella. 



The femur is about half as thick again as that of the right leg. Its 

 head is nearly normal in form, articulating with the rather shallow 

 acetabulum. The lesser trochanter and the internal border of the femur 

 are nearly normal. Anteriorly and externally there are the following 

 parts. Upon the external border there is a projecting callosity, clearly 

 being a great trochanter in its nature. Internal to this there is a knob- 

 shaped, rounded protuberance, which in texture so closely resembles 

 the head of a femur that it is almost certainly of this nature. It is 

 rounded and smooth as though for articulation with an acetabulum, 

 though it stands freely. Between this tuberosity and the real head of 

 the femur there is a third tuberosity, apparently representing the end 

 of the great trochanter of that limb which has been spoken of as 

 "anterior." The peripheral end of the femur is nearly normal on its 

 inner side, while on the outside it is considerably enlarged. The ex 



