86 MATERIALS FOR A MEMOIR OX 



Herewith are given examples of the common cuboido-astraga- 

 loid articulation : 



Hyrax (not marked), Macropus, 



Rhinoceros, Phascalarctos, 



Amy nod on, Dicotyles, 



Ungulata, Hippopotamus, 



Procyon, Erethizon (variable), 



Ursus, Arctomys, 



Erignathus, Myrmecophaga, 



Menodus, Elephas, 



Palseosyops, Equus (variable; sometimes 



Creodonta, calcaneo-scaplioid). 



Neither the calcaneo-scaphoid nor cuboido-astragaloid articula- 

 tion is found in the following : 



Dasyprocta, Orycteropus (variable ; tends 



Capromys, to calcaneo-scaphoid). 



Fiber, Homo (variable; sometimes 



Hystrix, calcaneo-scaphoid). 



Hyena crocuta, 

 While a fixed arrangement of the parts in an assumed oblique 

 axis is thus undetected, the examination was fruitful of one result, 

 — namely, that when in addition to the axial disposition of the 

 tarsal bones one to another and the lateral adaptation of parts in 

 transverse rows was departed from, the departure took place in 

 one of two ways, — either by the calcaneum reaching the scaphoid 

 {i.e., by a direction downward and inward) or by the cuboid bone 

 reaching the astragalus {i.e., by a direction upward and inward). 

 It is thus demonstrable that the elements in the tarsus which first 

 distribute the weight of the outer border of the foot as it comes 

 to the ground transmit the impact imoard in an oblique manner, 

 and, it may be assumed, tend to throw the weight of the limb 

 towards its axial line, which sustains the weight of the body 

 when the limb is in the vertical position. 



In the study of the phylogeny it will be seen that the more 

 distal of the two bones is first pressed inward, and that this 

 arrangement obtained not only in the first (with the exception of 

 Coryphodon), but in most of the extant forms. Why it should 

 ever have departed from this arrangement and reversed the in- 

 ward impact to the calcaneum is not an easy question to answer. 



