No. I.] THE SKULL IN THE MOSASAURID^E. ly 



anterior branch is a thin plate of bone attached to the lower 

 posterior and inner end of the palate. The pterygoids are 

 completely separated from each other, but are very near to- 

 gether, where they join the basipterygoid processes. The 

 upper face contains in this region a very distinct fossa for the 

 epipterygoid (columella). 



T/te Epipterygoid. 



This element does not differ from the simple bone in 

 Varanus. 



The Palatines (Fig. lo). 



The shape of the palate is best seen in the figure. Its outer 

 end, which is strongest, is connected with the posterior branch 

 of the maxillary, its posterior and inner end to the pterygoid, 

 its posterior upper process to the prefrontal. The long anterior 

 slender process is overlapped by the vomer. The outer wing 

 of the palatine is not perforated by a foramen. The palatines 

 are completely separated from each other. 



The Vomer (Fig. 9). 



The shape of the vomer is given in the figure. The vomers 

 are long slender bones, touching each other in front. They are 

 connected with the premaxillary, maxillary, and palate. They 

 are pierced by a foramen, as in Varanus. 



The Ectopterygoids. 



When I wrote my preliminary note {Scietice, Nov. 2, 1890), I 

 considered the elements which I now hold to be the super- 

 ciliaria as the epipterygoids, their shape agreeing exactly with 

 the description of the "transverse bone " by Marsh, I.e., "It is 

 an L-shaped bone, thin and somewhat twisted." I have now 

 the opinion that the element which I had considered at this 

 time as the interclavicle may be the true ectopterygoid. 



The Quadrates (Figs. 18, 19). 



I have nothing new to add to the descriptions of this element 

 by Dollo. The shape of the bone can be seen in the figures 

 18 and 19. 



