ON THE VERTEBRATE SKELETON. 335 



proportions and developes that process from its proximal end, the want of 

 which in man and most mammals deceived Vicq d'Azyr, as it has misled, 

 more recently, M. Cruvelhier. The complex explanation of the serial homo- 

 logies of the bones of the upper and lower extremities proposed by the last 

 named pains-taking anthropotomist*, involves more unnatural transpositions 

 and combinations of the parts than those of the D'Azyrian hypothesis, which 

 its ingenious author could not but admit seemed paradoxical ; viz. that the 

 anterior member of one side of the body repeated or corresponded with the 

 posterior member of the opposite side. Cuvier, however, seems to sanction 

 this idea by repeating the statement of Vicq d'Azyr, " C'est la droite d'une 

 paire, qu'il faut comparer a, la gauche de l'autret." 



M. Flourens has exposed in detail the fallacies of this view in an excellent 

 memoir in the ' Annales des Sciences' for 1838 (t. x. p. 35) ; in which he 

 arrives at the same conclusions as Dr. Barclay, and from similar considera- 

 tions from Comparative Anatomy, as to the serial homologies of the bones of 

 the fore-arm and leg ; and he confirms those of the carpal and tarsal bones, 

 which had been so truly and acutely discerned by Vicq d'Azyr. 



In mammalian quadrupeds generally the fore-limb takes the greater share 

 in the support, the hind-limb in the propulsion of the body. The manus is 

 accordingly commonly shorter and broader than the pes ; this may be seen in 

 the terminal segment of even the monodactyle hand and foot of the horse. 

 Consequently the transverse direction prevails in the arrangement of the 

 carpal bones and the longitudinal in that of the tarsal bones. 



The diiference is least in the carpus and tarsus of the long and slender fore- 

 and hind-hands of the quadrumana. If the carpus of the chimpanzee, for 

 example, be compared with that of man, the first difference which presents 

 itself is the comparatively small proportion of the scaphoid which articulates 

 with the radius, as compared with that in man, in whom the distal articu- 

 lation of the radius is equally divided between the scaphoides and lunare 

 which are on the same parallel transverse series. In the chimpanzee and 

 orang, on the contrary, the scaphoid is elongated, and extends, almost as much 

 from the os lunare as from the radius, along the radial side of the carpus, to 

 reach the trapezium and trapezoides ; it is, as it were, interposed between the 

 lunare of the proximal row and the trapezium and trapezoid of the distal row 

 of the carpal bones. The similarity of its connections, therefore, in the carpus 

 with those of the scaphoid in the tarsus (fig. 25, sc.)t is so close that the 

 serial homology of the two bones is unmistakeable. The astragalus (ib. a), 

 then, in the foot, repeats the os lunare (/) in the hand, but usurps the whole 

 of the articular surface of the tibia, and presents a larger proportional size, 

 especially in man, whose erect position required such exaggerated develop- 

 ment of the astragalus, or homotype of the lunare. The prominent part of 

 the calcaneum obviously repeats the prominent pisiforme (p), and the body 

 of the calcaneum (cl) articulates with the fibula as the cuneiforme (cu) 

 articulates with the ulna. The strain upon the homotype of the pisiforme to 

 produce the required effect in raising the back-part of the foot with its super- 

 incumbent weight upon the resisting ends of the toes, required its firm 

 coalescence with the homotype of the cuneiforme ; in other words, the cunei- 



* " L'extremite superieure du tibia est representee par la moitie superieure du cubitus, 

 et la moitie inferieure du tibia par la moitie inferieure du radius ; tandis que le perone est 

 represente par la moitie superieure du radius et par la moitie inferieure du cubitus." — Anato- 

 mie Descriptive, t. i. p. 315. 



f Lecons d'Anat. Comp. t. i. 1836, p. 342. 



X The carpal and tarsal bones are indicated rliagrammatically in fig. 25 ; their ossification 

 has not commenced at the period of the embryonic skeleton there represented. 



