10 V i nver sit y of California Publication a. [Geology 



gives the erroneous impression that the inner toe is set farther from 

 the middle of the foot than is the case with the outer toe. The outer 

 profile begins to trend away from the central axis sooner than does the 

 inner border and thus the concavity is more gradual. The two lateral 

 toes are on almost the same level and show but slight discrepancy in 

 size. 



Passing down the middle of the shaft at the bottom of the furrow is 

 an intermuscular line. Its proximal end arises near the rugosity of the 

 tibialis anticus just external to the median line. Thence it trends down- 

 ward and inward, crossing the median line slightly above the middle 

 point of the shaft. At a point about three-fourths the way down, it 

 crosses the median line again in a more positive curve to divide into 

 an inner and an outer branch going to the inner and outer intertro- 

 chlear spaces. A second intermuscular-line occupies the summit of the 

 outer ridge of the anterior furrow for about the middle half of its length. 



As seen from the rear, the head bears the great mound of the hypo- 

 tarsus, roughly triangular with its longest side almost horizontal but 

 declined toward the exterior, its most obtuse angle in the median line 

 downward, its shortest side facing downward and outward. Its face 

 is divided nearly on the median line by a low ridge into a larger internal 

 concave surface and a smaller external concave surface. On either side of 

 the hypotarsus the bone is excavated abruptly, thus leaving the hypo- 

 tarsus concave on either side parallel to the sagittal plane. 



From the median line of the hypotarsus a high rounded ridge passes 

 down the shaft for about one-fourth its length to merge into the flat 

 posterior surface of the shaft. In the region of the trochlea the palmar 

 surface is only slightly concave. The perforation for the anterior tibial 

 artery seems very small. 



The ridges passing down this aspect of the tarsus are three in number. 

 An inner and an outer limiting ridge pass from the corresponding extreme- 

 ties of the head to the inner and outer trochleae. A median ridge starts 

 on the external side of the hypotarsus, trending still farther outward to 

 return to the median line just above the foot. The line throughout its 

 length thus remains very slightly concave from the inner side. 



A view of the proximal articular surface shows the two facets sub- 

 equal in size with the outer slightly the larger. The outer facet is 

 longest in a plane parallel to the sagittal, the inner in a plane inclined 

 about forty-five degrees with the sagittal plane. Posterior to the inter- 

 cotylar tubercle lies a broad depression opening backward toward the 

 hypotarsus where it merges into a narrow and sharply defined transverse 

 groove separating the hypotarsus from the head. Seen from this direction 

 the hypotarsus seems almost block-like. Its margin toward the head 

 marked by the almost straight groove, its lateral margins slightly concave 

 and its posterior margin marked by two slight concavities. This block 

 appears fastened to the head nearer to the outer side than to the 

 inner. 



The view of the trochleae from the distal end shows the arch of the 

 foot to be very slight and the inner toe but little behind the outer, 

 The middle trochlea is very symmetrical. Its groove occupies the median 



