68 



terior sacral vertebrae and the terminations of the transverse processes, which 

 form the strongly developed ridges {i, i) extending from the posterior superior 

 angles of the ilia to the tuberosities of the ischia. Five of the posterior sacral 

 foramina (A:, k) open into these depressions, which foramina increase in size as 

 they recede backwards ; the last foramen is of an elliptical form, and measures 

 two inches by one in diameter. 



The expanded plates of the ilia are slightly convex posteriorly*, and the 

 labium is bent forwards so as to appear of unusual breadth, but really forming 

 the upper or anterior boundary of a deep cavity on the internal and anterior 

 part of the platef. The large fasciculi of the glutsei muscles are strongly indi- 

 cated by the ridges of bone on the back part of the ilium, which have shot up 

 in their interspaces, and by which their general course may be traced in the 

 fossil. The whole of this surface for muscular attachment is bounded anteriorly 

 by a nearly regular semicircular ridge of bone, dividing it from the broad and 

 deflected labial surface. This surface J becomes gradually narrower to the an- 

 terior superior spinous process or angle. The acetabula {m, in) are deep cavities 

 of an ovate form, with the long axis directed forwards and outwards : the plane 

 of the cavity looks obliquely outwards, downwards, and a little backwards. The 

 Harderian depression extends from the part of the acetabulum which is next 

 the obturator foramen, to the middle of the articular cavity, decreasing in breadth 

 and increasing in depth as it descends. The inlet of the small pelvis is of an 

 eUiptical form, with a vertical diameter of twenty inches and a transverse one 

 of twelve inches. There is no ilio-pectineal ridge or process on the part cor- 

 responding with the brim of the pelvis. 



The pubic bone§ rapidly contracts after leaving the acetabulum into a slender, 

 straight subcompressed osseous style, bounding the upper part of the obturator 

 foramen (o, o). It expands at the lower part of this foramen to blend with the 

 ischium, and the plate of bone thus constituted passes inwards to join the cor- 

 responding plate at the symphysis pubis (n), where they are anchylosed together : 

 the symphysis is very short, measuring only three inches in antero-posterior dia- 

 meter : its anterior and outer part is produced into an angular tubercle. The 

 under part of the acetabular extremity of the pubis is excavated by the canal for 



• PI. X. fig. 2. t PI- I- 



J PI. X. fig. 1. /. § Fig. 2.;>. 



