PELVIC ARCH 



153 



elements of the pelvis usually become ankylosed. The pubis actually 

 meets its fellow in the middle line only in Struthio, and the ischium 



FIG. 113. PELVIS OF Ap!try.c fiuitraliy. Lateral view. (After Marsh.) 



a, acetabulum ; if, ilium ; '*, ischium ; p, pectineal process from the pars 

 acetabularis ; p\ pubis. 



(dorsally) only in Rhea. A process given off from the posterior end 

 of the pubis in the Emu, and extending forwards, may represent an 

 epipubis. 



In Archaeopteryx, all the elements of the pelvis were 

 independent and relatively small, the ilium coming into relation 



Fn;. 114. RIGHT HALF OF THE 

 HUMAN PELVIS, LATERAL VIEW. 



Fo, obturator foramen ; the three 

 bones ilium (//), ischium (/#), and 

 pubis (P) are shown distinct from 

 one another in the acetabulum. 



FIG. 115. DIAGRAM SHOWING THE 

 RELATIONS OF THE PARS ACE- 

 TABULARIS in Viverra ciretta. 



A, acetabular bone ; Ac, acetabulum ; 

 ./, ilium ; ./<*, ischium ; P, pubis. 



with about six vertebrae only, and the pubis and ischium being 

 less backwardly directed than in recent Birds. 



