PHYLUM CHORD ATA 



341 



rabbit the skeleton of the limbs is constructed on a general 

 plan, common to the limbs of all Craniata but the fishes, 

 and known as the pentadactyle, in allusion to the five digits 

 in which the limb typically terminates. In the pectoral 

 limb the upper arm has a single long bone known as the 

 humerus ; at its proximal end this is movably articulated 

 with the pectoral arch. The forearm contains two long 



SCP 



B 



FE 



PU 



mils. 5 



J57 



FIG. 214. Diagrams of the fore (A) and hind (B) limbs with the limb-girdles. actb, 

 acetabulum; gl, glenoid cavity; p. cor, procoracoid; I-V, digits. Cartilage 

 bones cn.i, cn.2, centralia; COR, coracoid; dst. 5-1, distalia; FE, femur; 

 FI, fibula; fi, fibulare; HU, humerus; IL, ilium; int, intermedium; IS, 

 ischium; mtcp. 1-5, metacarpals; mt. ts. 1-5, metatarsals; ph, phalanges; 

 PU, pubis; RA, radius; ra, radiale; TI, tibia; ti, tibiale; UL, ulna; ill, 

 ulnare, membrane bone; CL, clavicle. 



bones radius and ulna articulating proximally with the 

 distal end of the humerus. The skeleton of the hand con- 

 sists of three principal parts, the carpus, the metacarpus, 



