302 University Geological Survey of Kansas. 



but I am far from certain that these belong to I. acanthicus. If 

 they prove not to be this, I would propose the name of Ichthyo- 

 dectes parvus for them. 



The maxilla is long and slender, with the superior border 

 moderately curved back of the posterior condyle. This condyle 

 is slightly convex, and is invaded by a notch from behind. The 

 surface for the premaxilla is bent inward to a considerable ex- 

 tent, and has a small tubercular condyle above and in front. 

 The alveolar border is somewhat concave anteriorly, thin, and 

 bears a row of teeth which do not seem to decrease much in size 

 toward the posterior extremity. The teeth are cylindrical in 

 cross-section, acutely pointed, and directed slightly inward at 

 the apices. The premaxilla is thin and plate-like, with seven 

 teeth on the alveolar border. 



Premaxilla : Length of alveolar border 18 mm. 



Maxilla : Depth at posterior condyle 19 " 



Length of alveolar border (estimated) 77 " 



Number of teeth in one centimeter. 8 



Besides being smaller in size, the alveolar border does not 

 have the two convexities found in I. anaides, but is convex in 

 front and slightly concave in the middle and posterior portions. 

 The symphyses are but slightly sloping and not much thick- 

 ened. The coronoid process is poorly developed and the border 

 back of it slopes gradually to the cotylus. The teeth are cyl- 

 indrical in cross-section and directed slightly inward. The derm- 

 articular extends well forward in a long, sword-shaped process 

 which is very robust below. The antarticular is wedge-shaped 

 and similar in general form to that of Xiphactinus. 



Dentary : Length of alveolar border 75 mm. 



Depth of symphysis 26 " 



Depth at coronoid process 33 " 



Number of teeth in one centimeter 4.5 



Only the anterior portions of the palatines are preserved, 

 which show the malleolar portions to be projected outward in a 

 manner similar to that found in I. hamatus, but differs from 

 this form in having them proportionally broader and not so 

 deep. The articular facet for the prefrontal is the smaller of 

 the two and is nearly flat, while the one for the posterior con- 



