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5. W. WILLISTON 



them. Lying just within the orifice there is a thin, plate-Hke bone, 

 evidently forming a turbinated structure, the sphenomaxillary. 



Not much can be added to my description of the temporal 

 vacuity. On the right side the orbital bar and inferior arcade 

 are nearly complete, but on the left side they have been injured 

 by the displacement of the quadrate. I think, however, as I 

 suspected, that the vacuity is a little smaller than I figured it. 



Nothing definite can be said 

 as to the presence of a distinct 

 quadratojugal bone. 



The palate, fortunately, is 

 in such preservation that its 

 structure, save in details, is 

 very clear. The whole sur- 

 face is closed, as in Pantylus, 

 and is covered with small, but 

 pointed, conical teeth. Large 

 orifices in front, corresponding 

 with those shown in the former 

 figure, are the nares, situated 

 immediately below the exter- 

 nal openings. The two sides 

 of the palate show divisions so 

 alike that one cannot resist the 

 conviction that some of them, 

 at least, are sutural separations. Especially do the divisions run- 

 ning backward from the nares, which are not only alike on the two 

 sides, but which agree with those of the former skull, indicate the 

 sutures between palatines and pterygoids. One cannot be sure of 

 the division between the pterygoids and vomers, covered, as the 

 surface is, with numerous small teeth, which cannot be entirely 

 freed from the matrix; but a symmetrical depression on the two 

 sides seems to indicate the sutures, as shown by dotted lines in 

 the figure. On either side behind, there are two divisions, which 

 seem to be exactly alike on the two sides, one running forward and 

 outward from the inner extremity of what would be the transverse 

 bones if present; the other forward and inward to near the front end 



Fig. 9. — Casea hroilii Williston : A , skull 

 from the side; B, left mandible of same, 

 from inner side, three-fifths natural size; 

 ^w, premaxilla; w, maxilla; ^0, postorbital; 

 7, jugal; d, dentary; sa, surangular; ang, 

 angular; sp, splenial; art, articular; pa, 

 prearticular; c, coronoid. 



