604 



BRITISH FOSSIL REPTILES. 



thus dividing the obturator interspace into a pair of foramina. As in all mammals 

 the bone is directed downward (hsemad) and a little backward. 



In Crocodilia the pubis (fig. \^, p b), as in birds, is a simple style slightly expanded 

 distally where it articulates with a cartilaginous abdominal sternum,* but it joins not 



Momtcr. C 



Kchidna. 



Modifications of pubis. The line A A traverses the corresponding part of the bone. 



there, directly, either its fellow or the ischium. It contributes no part to the acetabulum, 

 but is attached at its proximal end to an anteriorly produced part of the same end of the 

 ischium (ib. is). 



In Chelonia the pubis is remarkable for its breadth, due to its distal expansion ; 

 proximally it contributes to the acetabulum, articulating there with both ilium and 

 ischium, and at or near half way to the distal end, it sends forward a broad and termi- 



* ' Anat. of Vertebrates,' vol. i, p. 68, fig. 56, 5. . 



