PELVIC GIRDLE — REPTILIA 



265 



column are not connected. Usually ischium and ilium meet in the 



acetabulum which usually is a closed cup with imperforate bottom. 



Sqtjamata. — Except in the apodal forms, the pubis, transverse at 



first, changes its direction during development, so that it extends 



Fig. 285. — Lacertilian pelves: A, Monotor bivillatiis; B, Chameleo Hoffmann, '90). 

 e, epipubis? h, hypoischium; il, ilium; ipf, ischio-pubic fenestra; is, ischium; of, obturator 

 foramen; p, pubis; a, acetabulum; 



obliquely forwards and inwards (fig. 285), thus enlarging the fenestra. 

 Except in Chameleo, where it is nearly vertical, the ilium extends 

 downwards and forwards from the sacrum, with which it is movably 

 connected by cartilage and sacral ribs, 

 a part dorsal to the connexion often 

 persisting as cartilage. Usually carti- 

 lage persists in the ischiopubic sym- 

 physes and may extend from the pubes 

 nearly to the ischia, partly separating 

 the fenestrse. The ischiadic cartilage 

 is more frequently ossified. There is 

 usually a marked epipubis (sometimes 

 paired) occasionally ossified (in Cham- 

 eleo, figure 285 B, as two small rods). 

 The hypoischium, usually movable, 

 is well developed and may be carti- 

 lage or bone in the adult. Many 

 lizards have prepubic processes extend- 

 ing forwards and either inwards or 

 outwards. At times they are well- 

 developed, at others scarcely more than knobs on the antero-lateral 

 border of the pubes. All three pelvic bones meet in the imperforate 

 acetabulum. 



Fig. 286. — Pelves of apjojd[al 

 Squamates: A, B, Seps; C, Ophi- 

 saurus (lizards) ; D, Cylindrophis 

 (Fiirbringer, '70). /, femur; %i, 

 iliopectineal; il, ilium; ip, ischio- 

 pubis; p, pubis; t, tibia. 



