396 



ZOOLOGY. 



and are reduced to. cartilaginous pieces in sharks. The pelvic 

 girdle, or pelvis, consists of three bones, i.e., one dorsal, the 

 ilium, and two ventral, the anterior of which is called pubis, 

 and the posterior ischium. 



The limbs each consist of a single long bone, succeeded by 

 two long bones, followed by two transverse rows of short 

 wrist or ankle bones, and five series of long finger or toe 

 bones, called phalanges. For example, in the fore limb of 

 most Vertebrates, as in the arm of man, to the shoulder gir- 

 dle, i.e., at the point of junction of the three bones com- 

 posing it, is articulated the humerus ; this is succeeded by 



PIG. 379. 



Fio 380. 



FIG. a81. 



Fig. 379. Sternum and shoulder girdle of Frog (Sana 

 temporarta). p, body of the sternum ; sc, scapula ; sc', 

 supra-scapula ; co, coracoid bone, fused in the middle line 

 with its fellow of the opposite side (s) ; cl, clavicle ; e, epis- 

 ternum. The extreme shaded double portion below p is the 

 xiphisternum. The cartilaginous parts are shaded. After 

 Gegenbaur. 



Fig. 380. Fore-leg of a peal. S, scapula ; H^ humerus ; 

 0, olecranon or tip of elbow ; It, radius ; Z7", ulna ; Po, 

 pollex, or thumb. 



Fig. 381. Pelvis or pelvic bones on one side of a marsu- 



Sial (Kangaroo). 62, ilium; a, situated on the pubic bone 

 wbis) indicates the acetabulnm or concavity for the artic- 

 ulation of the head of the femur ; 63, iechium, consolidated with the pubis. The 

 three bones thus consolidated form the os innominatum ; m, marsupial bones ar- 

 ticulated to the pubic bones. After Owen. 



the ulna and radius, the wrist-bones or carpals, and the fin- 

 ger-bones or phalanges, the single row of phalanges forming 

 a digit (finger or toe). To the point of union (acetabulum, 

 Fig. 381, a) of the three pelvic bones is articulated the fe- 

 mur, or thigh; this is succeeded by the tibia and fibula 

 (shank-bones), the tarsal and metatarsal bones (ankle-bones), 

 and the phalanges or bones forming the digits (toes). 



Figs. 383-385 represent the simplest form of the posterior 

 limbs in the higher Vertebrates, that of the bird showing an 



