210 



ELEMENTAR Y ANA TO MY. 



[LESS. 



FIG. 180. RUDIMENTARY PELVIC 

 EXTREMITY OF 



_f, fibula ; t, tibia. 

 (After Fnrbrin^er.') 



It may be that the metatarsals coalesce with the distal part 

 of the tarsus, as in Birds, the 

 Chameleon, and Bradypus. 



Metatarsals may coexist each 

 with only one if any phalanx, as 

 in Ophiodes. The first metatar- 

 sals may widely diverge from the 

 line of the others, as in non- 

 human Primates, and in some 

 Marsupials, e.g. Phalangista. 



A more complete divergence 

 or opposition, however, may 

 exist, as in most Birds ; or as in the Chameleon, where the 

 two tibial metatarsals are 

 opposed to the three peroneal 

 ones ; or as in Parrots, where 

 the first and fourth are op- 

 posed to the second and 

 third. 



In the number of these 

 bones and their sub-equality 

 of development man agrees 

 with a great number of Verte- 

 brates above Fishes. Never- 

 theless, the number may be 

 much reduced, and the pro- 

 portions of the several bones 

 may vary in different modes. 

 Thus there may be but a 

 single metatarsal, the third, 

 with rudiments of the second 

 and fourth, as in the Horse ; 

 or but a single large one, the 

 fourth, with the second, third, 

 and fifth metatarsals very 

 small, as in Chceropus. 



There may be but a single 

 bone, which consists of the 

 third and fourth fused to- 

 gether, as in the Sheep, Deer, 

 c., and in the Ostrich ; or of 

 second, third, and fourth fused 

 together, as in the Jerboa and 

 the Emeu ; or of these and the first also, as in many Birds. 



FIG. 181. BONES OF RIGHT FOOT OF 

 Chaeropus castanotis (nat. size). 



a, astragalus ; c, calcaneum ; cb, cu - 

 boides ; c *, ecto-cuneiforme ; , na- 

 viculare ; II. III. IV. and ^., second, 

 third, fourth, and fifth digits. 



(From Flower s " Osteology. ") 



