CARPUS AND TARSUS. . 41 



§ 83. Marsh has proposed {!) to apply general names to the corresponding hones of 

 the arm and leg. Th us, the bones of the proximal segments are the Oaaa propodialia ; 

 the radius and ulna, the tibia and fibula, constitute the epipodialia; the bones of the 

 carpus and tarsus are mesopodialia ; the metacarpalia and metatarsalia are — as indeed 

 they have previously been called — the metapodiaZia, and the old term phalanges is 

 retained for the bones of the digits and dactyls. 



§ 84. Carpus and Tarsus. — The carpalia (bones of the carpus), and 

 the tarsalia (bones of the tarsus), are yariously interpreted by different 

 writers ; see Balfour, A, II, 508. 



The following general description, based chiefly upon the researches of 

 Gegenbaur, is given by Huxley, A, 31 : — 



" There is reason to belieye that, when least modified, the carpus and 

 the tarsus are composed of skeletal elements which are ahke in number and 

 arrangement. 



" One of these, primitively situated in the centre of the carpus or tarsus, 

 is termed the centrale ; on the distal side of this are five carpalia, or tarsalia, 

 which articulate with the several metacarpal or metatarsal bones ; while, on 

 its proximal side are three bones — one radiale or tihiale, articulating with 

 the radius or tibia ; one ulnare or flbulare, with the ulna or fibula ; and one 

 intermedium, situated between the foregoing. 



" Carpal and ta,rsal bones or cartilages, thus disposed, are to be met with 

 in some Amphibia and Cholonia, but, commonly, the typical arrangement is 

 disturbed by the suppression of some of these elements, or their coalescence 

 with one another. 



" Thus, in the carpus of man, the radiale, intermedium, and ulnare are 

 represented by the scaphoides, lunare, and cuneiforme respectively. The 

 pisiforme is a sesamoid bone, developed in the tendon of the M. flexor carpi 

 ulnaris, which has nothing to do with the primitive carpus. The centrale 

 is not represented in a distinct shape, having probably coalesced with one of 

 the other elements of the carpus. The fourth and fifth carpalia have 

 coalesced, and form the single urwiforme. See § 421. 



"In the tarsus of man the astragalus represents the coalesced tibiale and 

 intermedium ; the calcaneum the fibulare. The naviculare {scaphoides of 

 Anthropotomy) is the centrale. Like the corresponding bones in the 

 carpus, the fourth and fifth tarsalia have coalesced to form the cuhoides." 



§ 85. In the cat, so far as we can judge from the figures and statements 

 of Flower (36, 138), and Mivart (B, 96, Fig. 60), and from our own 

 observations, the condition of things is as follows : — 



In the tarsus, aside from peculiarities of shape, the tarsalia and their 

 connections are as in man. 



In the carpus, the same is the case, excepting that the scapho-lunare 

 represents not only the scaphoides and the lunare — the radiale and inter- 

 medium of the primitive carpus — ^but also the centrale. Flower found 



