THE ENDOSKELETON 



179 



Jacts which forbid us from imagining that it is really a primi- 

 tive condition. Thus the animal in which it comes to its most 

 perfect realization is the turtle, the carpus of which is almost 

 diagrammatic, while the salamanders, where a more primitive 

 type is to be expected, depart almost as widely from the dia- 

 grams as do the mammals. From certain indications it seems 

 probable that in the early carpus and -tarsus there were two 

 centralia (Fig. 48, a), and that the separate bones were ar- 



Ill IV 



FIG. 48. Various forms of carpus. Figures (a)-(c) after ELISA 

 NORSA; figure (e), after FLOWER. 



(a) Sphenodon (Hatteria), a New Zealand lizard, (b) Chick embryo, early 

 stage. (c) Chick embryo, later stage, (d) Lacerta, a European lizard, (e) Talpa, 

 European mole. (f) Pig. 



R, radius; U, ulnar; r, radiale; u, ulnare; i, intermedium; c, centrale; 1-5, car- 

 palia; p, pisiforme; f ; os falciforme; I-V digits. 



ranged, not symmetrically, but in oblique rows continued more 

 or less directly to the digits, and suggesting the derivation of 

 both carpus [and tarsus] and digits from long fin-rays, divided 

 into numerous joints. 



In the nomenclature of the carpal and tarsal bones em- 

 ployed in human anatomy we have an unusually good illustra- 



