346 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Suborbital 1. 



This is roughly rectangular in shape, the dorsal edge be- 

 ing shorter than the ventral, as the two dorsal corners are cut 

 off. A section of the bone is triangular at the posterior end, 

 the anterior end being thin. The lateral face is convex on the 

 long axis, and is marked by five foramina, the three larger con- 

 necting with each other by a canal. All of the suborbitals have 

 at least two foramina, and they are all connected and make a 

 canal through the whole ring. The upper face of the first is 

 indented by a notch which fits over a double notch on the pre- 

 frontal, giving the ring a good articulation at the anterior end. 

 The articulation of suborbital 1 and suborbital 2 is trian- 

 gular. Suborbital 1 is cut off posteriorly at the expense of the 

 dorsal face, making a triangular face for the articulation with 

 suborbital 2. 



Suborbitals 2, 3, U- 



These are very much alike in shape. The ventral edge of 

 each is about twice as long as the dorsal, making a notch in 

 the posterior end of each, into which the next suborbital fits. 

 All three are triangular in section, with the base of the triangle 

 ventral. All have a foramen at each end, posterior and an- 

 terior, and all are connected by a canal. Each of the sub- 

 orbitals projects posteriorly under the succeeding bone. 



Suborbital 5. 



The fifth is differently shaped and does not enter -into the 

 ventral face of the ring. The sixth suborbital sends a pro- 

 jection anteriorly to meet the posterior projection of suborbital 

 4, so that suborbital 5 is above. 



Suborbital 6. 



The sixth meets the projection of the fourth on the ventral 

 border of the ring. It is about twice as long as wide, the pos- 

 terior end being irregular, making a dentate suture with the 

 seventh. 



Suborbital 7. 



The seventh, and the last of the ring, is wider at the posterior 

 end than at the anterior. It articulates with the frontal, which 

 has a deep depression for this articulation. There is a canal 

 on the frontal, continuous with the canal extending through 

 the ring. The whole ring is covered with small tracings, which 

 do not show in the drawing. 



