THE PECTORAL AND PELVIC GIRDLES 



143 



cotylosaur reptiles in early Permian times. The ilium of the rhachi- 

 tomous forms is not dilated above, as in the reptiles, but even this 

 distinction fails in the more nearly allied embolomerous Cricotus, in 

 which the ilium is prolonged backward, quite as in the reptiles. The 

 pubes and ischia meet in a close symphysis without openings of any 

 kind, except the pubic foramen, a small hole through the pubis below 



Fig. II4. Pelvic girdles: A, Cacops (Temnospondyli), from below. One half natural size. 

 B, Seymouria (Cotylosaur), from below. A little more than one half natural size. C, D, 

 Varanops (Theromorpha), below and from the side. 



the margin of the acetabulum, in front of the ischiatic suture, for the 

 passage of the obturator nerve. This " plate-like " structure of the pel- 

 vis is characteristic of the Cotylosauria (Figs. 114 b, 115), and more 

 or less of the Theromorpha (Figs. 114 c, 117), Therapsida (Fig. 119), 

 Proganosauria, the Choristodera, and early Rhynchocephalia. 



