310 



ANATOMY OF VERTEBRATES. 



The ' serial homology ' of the parts of the respective arches of 

 these limbs is illustrated in Vol. I. p. 188. In the limbs them- 

 selves, or appendages of the arches, the femur, fig. 195, a, answers 

 to, or is the homotype of, the humerus, fig. 190, a\ the tibia, fig. 

 195, u, is the homotype of the radius, fig. 190, o\ the fibula, fig. 

 195, 1, 2, of the ulna, s, u: the tarsus repeats the carpus, the 

 metatarsus the metacarpus, and the three phalanges, as respec- 

 tively named ' proximal,' ' middle,' and ' distal ' or ' ungual.' In 

 the tarsus it will be seen that the cuboid, in the ' Elephant,' fig. 

 193, ^, supports the two outer metatarsals, as does the unciforme 

 the two outer metacarpals, in the Orang and Man, fig. 191, u: 



the ectocuneiform in the tarsus, ce, and 



195 



the 



m 



the 



carpus. 



771, re- 



sj)ectively support the middle digit, iii : 

 the mesocuneiforme, mc, holds the 

 same ^ serial ' relation to .the trape- 

 zoides, fZ, and the ' entocuneiform,' ec, 

 to the ^ trapezium,' t. The bone of the 

 carpus, fig. 191, 5, in Man articulates 

 with the three innermost carpals of the 

 second row ; and, in the Orang, but 

 in a divided state, s and s', leaves a 

 larger share of the v\a'ist-joint with the 

 radius to the bone Z, and in the same 

 degree tends to repeat in the carpus 

 the position and connections of the bone 

 s in the tarsus : so I infer that the 

 carpal scaphoid and tarsal naviculare 

 are homotypes : the carpal lunare, fig. 

 191, I, answers to the tarsal astragalus, 

 and the carpal cuneiforme and pisi- 

 forme to the tarsal calcaneum, in which 

 bone the lever-process forming the 

 'heel' more immediately repeats the 

 pisiforme, which also in many quadru- 

 peds, fig. 191, j9. Hyaena, makes a 'heel- 

 like ' projection in the carpus. 



§ 178. Special Homologies. — As that 

 which is engendered by a Mammal is 

 mammalian from its beginning, each 

 step of its building up has the finish- 

 ing of the Mammal for its end, and 

 shows it the more as it nears the goal. The developemental phe- 



Boncs of liind-limh, Horse 



