THE SKULL OF REPTILES 



6i 



boundary of the orbits, with their usual articulations. The jugals 

 are long, articulating with postorbitals, quadratojugals, maxillae, 

 and lacrimals. The relations of the bones of the palate and the 

 boundaries of the nares are primitive; an ectopterygoid has not been 

 recognized and is probably absent; there are no teeth on the palatal 



Fig. 50. Ichthyosaur skull: Eaptanodon {Ophthalmosaurus) , from the side, from 

 above, and from below. After Gilmore. 



bones. On the occiput the paroccipitals, unlike all other reptiles since 

 the primitive Cotylosauria, save the Chelonia, are separate. The 

 stapes is a short, stout bone, possibly an acquired, more probably a 

 primitive, character. There are no dermosupraoccipitals. The large 

 parietal foramen is at the front end of the parietals, sometimes be- 

 tween the frontals. 



Most characteristic of the ichthyosaur skull is the structure of the 

 temporal region, about which there has been dispute from the time of 



