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THE SKULL OF REPTILES
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The Skull of the Cotylosauria
(Figs. 1–9, 12, 13, 16 d, e, 17–24, 25 b, c, 26–29)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/The_Osteology_of_the_Reptiles_p33_Fig-19.png/240px-The_Osteology_of_the_Reptiles_p33_Fig-19.png)
Fig. 19. Seymouria haylorensis. Cotylosaur skull: from above. One half natural size, n, nasal; l, lacrimal; pf, prefrontal; pof, postfrontal; fr, frontal; it, intertemporal; st, supratemporal; do, dermoöccipital; t, tabulare.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/The_Osteology_of_the_Reptiles_p33_Fig-20.png/420px-The_Osteology_of_the_Reptiles_p33_Fig-20.png)
Fig. 20. Seymouria haylorensis. Skull and pectoral girdle: from the side. One half natural size, pm, premaxilla; m, maxilla; l, lacrimal; n, nasal; pf, prefrontal; j, jugal; po, postorbital; sq, squamosal; qj, quadratojugal; cl, clavicle; ic, interclavicle; 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