LAW OF SIMPLIFICATION OF FEET. 



185 



pophyses, d^ are developed: tlie more expanded haemal 

 arch consists of the plenrapophyses, pl^ and the hsemapo- 

 physes, h; the former is called the "ilium," 62, the latter 

 the "ischium," 63; and, as the hsemapophyses of another 

 segment are usually added to the scapular arch, when 

 they receive the name of " clavicles," so also the ha3ma- 

 poph3^ses of a contiguous segment are usually added to 

 the pelvic arch, when they are called "pubic bones." 



The pelvic diverging appendage, a a, has advanced to 

 the same stage of complexity in the proteus, as the scapu- 

 lar one in the amphiuma; the first ossified segment is 

 called " femur," 65 ; the divisions of the next segment 

 are respectively termed "tibia," %Q^ and "fibula," 67 ; the 

 first set of short bones in the "pes," or foot, are called 

 " tarsals," Q^ ; those of the two toes are called " meta- 

 tarsals" and " phalanges," 69. 



The tarsal bones, from the desfree of constancv of their 

 forms and relative positions, have re- 

 ceived distinct names. In Fig. 35 of 

 the bones of the hind-foot in the horse, 

 a marks the " astragalus," c/, the " cal- 

 caneum," or heel-bone, the j^rominent 

 part of which forms the "hock ;" s is the 

 " scaphoides," or naviculare, 5, the "cu- 

 boid," C6, " cctocuneiform," and C7??, the 

 " mesocuneiform." Now, the cctocunei- 

 form in all mammalia supports the third 

 or middle of the five toes when they 

 are all present, the mesocuneiform sup- 

 ports the second toe, and the cuboides 

 the fourth and fifth. We see, therefore, 

 in the horse, that the very large bone 

 articulated to the cctocuneiform 



16* 



ce, IS 



