396 



ZOOLOGY. 



and are reduced to cartilaginous pieces in sharks. The pelvic 

 girdle, or pelvis, consists of tiiree 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 liimierus ; this is succeeded by 



Fig. 379 



Fio! 380. 



Fig. .379.— Sternum and shoulder girdle of Prog {RaiM 

 tempora'i^i). p, body of the sternum ; fic, scapula ; ^e\ 

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

 with its fellow of the opposite side (.s) ; d. clavicle ; e, epi>^- 

 ternum. The extreme shaderl double portion below /> is the 

 xiphistemum. The cartilaginous parts arc shaded.— After 

 Gegenbanr. 



Fig. 380.— Fore-leg of a seal. S, scapula ; H, humerus ; 

 O, olecranon or tip of elbow ; S, radius ; U, ulna ; Po. 

 pollex, or thumb. 



Fig. 381.— Pelvis or pelvic bones on one side of a mar-u 

 pial (Kangaroo). 62, ilium; a, situated on the pubic bohc Fig. 381. 



{pubis) indicates the acetabulum or concavity for the ariic- 



ulation of the head of the femur; 63, ischium, 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 tilna 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 {acetahulum. 

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

 mur, cr thigh; this is succeeded by the tiUa 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 



