140 



E. C. CASE 



to make out the sutures distinctly in all cases. Among the peculiari- 

 ties of the palate are the following: There are no buttresses for 

 the lower jaw on the outer portion of the pterygoids. The pterygoids 

 end anteriorly on the upper surface of the maxillary, with a very 

 degenerate transverse separating them only partly. The pterygoids 

 touch the vomer only at the extreme posterior end, if at all. Because 

 the palatines do not extend inward to meet in the middle line, there 

 is a great median vacuity which is divided by the vomer. Into this 

 vacuity the anterior nares open directly (Figs. 4 and 5). 



The lower surface of the skull roof is marked by two descending 

 processes which originate just posterior to the pineal foramen and 

 extend forward well anterior to it. The lower ends of the processes 

 are not preserved, but they are in the position of the descending 

 plates of the parietal bones found in the turtles. Cope describes 

 them as alisphenoids and mentions their extending forward to carry 

 the brain case between the orbits. The upper ends of the plates 

 are fused with the lower surface of the parietals, so that they cannot 

 be reckoned as epi-pterygoids. Immediately in front of these two 

 processes there is a wide process on the lower surface of the skull 

 in the median line, so that it in some measure closes the anterior 

 end of the space between the paired processes. This median pro- 

 cess is continued forward and downward as a thin plate which lies 

 immediately above the vomer, but in no specimen of the collection 

 can be shown to connect with it. Possibly the two were united by 

 cartilage. I take this median plate to be the forward and upward 

 continuation of the basi-cranial axis, the ethmoid. 



The lower jaw. — Except for the teeth, the lower jaw is peculiarly 

 testudinate in appearance. The anterior portion has a relatively 

 great height, due largely to the dentary; but there is a very incon- 

 spicuous coronoid process. The bones, like those of the upper por- 

 tion of the skull, are so closely united that the sutures are almost 

 unrecognizable. 



The inner surface is marked by an enormous opening into the 

 Meckelian groove. This opening is separated from one equally 

 large on the superior surface of the posterior portion of the bone by 

 a narrow bridge, presumably formed by the splenial. The cavity 

 of the Meckelian groove is large, so that the jaw is practically a shell 



