THE SKULL OF REPTILES 



33 



The Skull of the Cotylosauria 



(Figs. I-Q, 12, 13, 16 D, E, 17-24, 25 B, C, 26-29) 



Fig. 19. Seymouria haylorensis. Cotylo- 

 saur skull: from above. One half natural 

 size, n, nasal; /, lacrimal; pj, prefrontal; 

 pqf, postfrontal; /r, frontal; /'/, intertem- 

 poral; St, supratemporal; do, dermoocci- 

 pital; /, tabulate. 



Fig. 20. Seymouria haylorensis. Skull and pectoral girdle: from the side. One half 

 natural size, pm, premaxilla; m, maxilla; /, lacrimal; «, nasal; pf, prefrontal; j, 

 jugal; po, postorbital; sq, squamosal; qj, quadratojugal; cl, clavicle; ic, inter- 

 clavicle; sc, scapula; c, coracoid. 



But few modifications of the primitive characters of the skull are 

 known in this order. The parietal foramen is absent in one or two 



