Stewart.] Cretaceous Fishes. 277 



one end and contracted into an elongated, narrow and some- 

 what thickened process at the other, at the extremity of which 

 there is a roughened surface which probably gives attachment 

 for cartilage. On one side of this process there is a long, thin 

 lamina of bone extending toward the narrow extremity, and so 

 closely applied to it that at first sight it has the appearance of 

 being the border of a groove on the edge of the process. The 

 expanded end is thickened and bears a small articular surface, 

 the face of which is almost in line with the process mentioned 

 above. This bone was figured by Cope 83 as a "?hyomandibu- 

 lar,'" which has since been shown to be incorrect. 



The second of these, fig. 2, is represented by portions of two 

 bones, neither of which is complete. They are thin on one bor- 

 der, while the other is much thicker and is invaded by a shallow 

 groove. This thickened portion was probably continued out- 

 ward in a process beyond the end of the bone. The third, fig. 3, 

 is plate-like and more or less sculptured on both sides. On one 

 of the sides there is a broad, triangular-shaped depression, which 

 is invaded by a notch from the edge of the bone, and on the 

 other side there is a prominent ridge extending away from the 

 apex. I have found a bone almost identical with this in con- 

 nection with the supposed operculum of an unknown fish, which 

 will be discussed later. This was figured by Cope as an '* un- 

 certain bone." 3 * 



The fourth and last of these bones (fig. 4) I have described 

 a- probably an infraopercular, 35 but it is probably a fragmentary 

 coracoid. It is the largest of the four under consideration, and 

 is very thin and Hat, excepting near the posterior end, where it 

 suddenly thickens into a prominent ridge, which probably con- 

 tinues to the point where the bone articulates with the scapula. 



The hyomandibular is a large and somewhat triangular- 

 shaped bone, with the base of the triangle above, where there is 

 a long, narrow articular face for articulating this bone with the 

 pit on the side of the skull for its reception. The face is convex 



:«. Crefc Vert, Week, pi. XL. 



84. I.e.. pi. XL. 



35. Kan~. Univ. Quart., vol. VIII, v . >l, pi. XI. Off. I. 



