150 



COMPARATIVE ANATOMY 



a lightness of build. The rod-like pubis and ischium are separated 

 from one another by a large ischiopubic foramen, and between them 

 in the middle line is a longitudinal fibro-cartilaginous ligament, 

 continuous anteriorly with the plug-like epipubic cartilage and 

 posteriorly with the hypoischium or os cloacce (absent in Chame- 

 leons). This tract represents the remnant of the median ends of 



PP 



.15 



Fic4. 110. PELVIC ARCH OF VARIOUS CHELONIANS. From the ventral side. 

 A, Macrochelyx (after G. Baur) ; B, Sphargis coriacea (after Hoffmann) 

 C, Tetstudo ; D, Chelone. 



Cep, epipubic cartilage ; Fopi, ischiopubic foramen ; Hpls, hypoischiatic process ; 

 Is, ischium ; P, pubis ; PP, prepubis. 



the pubis and ischium which are present in the embryo ; and thus 

 in this, as in certain other respects, the pelvis of the Lacertilia 

 may be said to pass through a Hatteria-like stage in the course of 

 development. The ilium in some cases is almost vertical in posi- 

 tion : in others it is more oblique, sloping upwards and backwards 

 from the acetabulum. 



