INTRODUCTORY. THE LIMBS. 27 



three, the radiale, intermedium, and ulnare, the first being 

 on the radial side of the limb, and a distal row of five called 

 respectively carpale 1, 2, 3, 4, 5, beginning on the radial side. 

 Between these two rows is a single bone the centrale, or there 

 may be two. 



Similarly there are nine bones in a simple tarsus such as 

 that of Salamandra. They form a proximal row of three, the 

 tibiale, intermedium and fibulare, and a distal row of five, 

 called respectively tarsale 1, 2, 3, 4, 5, beginning on the tibial 

 side. Between the two rows there is a centrale as in the 

 carpus, or there may be two. 



The following names derived from human anatomy are 

 commonly applied to the various carpal and tarsal bones : 



Carpus. Tarsus. 



radiale = scaphoid tibiale ) 



,. ,. V astragalus 



intermedium = lunar intermedium] 



ulnare = cuneiform fibulare = calcaneum 



centrale = central centrale = navicular 



carpale 1 = trapezium tarsale 1 = internal cuneiform 

 ,, 2 = trapezoid ,, 2 = middle ,, 



,, 3 = magnum ,, 3 = external ,, 



" I Cuneiform " r l = 



5j ,, 5J 



cuboid 



NOTE. The above is the view commonly accepted concerning the 

 homology of the carpal and tarsal bones. But with regard to the 

 proximal row of tarsal bones there is difference of opinion. All anato- 

 mists are agreed that the calcaneum is the fibulare and that the inter- 

 medium is contained in the astragalus, but while the majority regard 

 the astragalus as the fused tibiale and intermedium, Baur considers 

 that a small bone found on the tibial side of the tarsus in Procavia, 

 many Eodents, Insectivores, and the male Ornithorhynchus, is the vesti- 

 gial tibiale, and regards the astragalus as the intermedium alone 1 . He 

 also considers that the mammalian scaphoid represents a centrale. 



1 G. Baur, Beitrdge zur Morphogenie des Carpus und Tarsus der 

 Vertebraten, Theil 1. Batrachia. Jena, 1888, and Amer. Natural., vol. xix. 

 1885 (several papers). 



