Stewart.] Cretaceous Fishes. 273 



aent and curved upward on the external side of the cotylus. 

 In addition to the above bones, there is another, which is not 

 mentioned by either Cope or Hay. Tt is a small bone, which 

 lies in front of the antarticular, and is marked sp. in the figure 

 of the lower jaw on plate XXXV. It presents a small facet 

 above, which seems to have had attachment with something. 

 This bone occupies about the same position as the splenial in 

 some fishes, which name I will give it provisionally. 



LeDgth of alveolar border 260 mm. 



Length of dentary from cotyloid cavity 325 " 



Depth at symphysis 94 " 



Depth at coronoid angle 136 " 



Length of articular from cotyloid cavity 224 " 



The above measurements are of a single specimen, No. 88 in 

 the following table, which shows the great variation in the size 

 of the mandible of this species : 



No. 



Length of 

 alveolar 

 border. 



Depth at 

 coronoid. 



No. 



Length of 

 alveolar 

 border. 



Depth at 

 coronoid. 



1 

 2 



242.5 



251 



279 



194 



260 



145.5 



144 



140 



109 



136 



179 

 266 

 275 

 279 

 287 

 301 

 314 

 353 



185 



94 



3 







4 







88 



210 





127 





132 







242 



195 



130 



135 



1117 

 215 





115 



155 





















The hyoid arch is represented by only one bone, the cerato- 

 hyal, and is the same bone figured by Cope :: " and described by 

 Crook 51 as an interopercular. The bone is elongated, and in out- 

 line is somewhat the shape of a parallelogram with one side 

 crushed in. The posterior end is the broader of the two and 

 b<-ars an elongated, narrow and concave facet for the articula- 

 tion with the epihyal. The anterior end is more irregular in 

 outline and bears two facets for the hypo- and urohyals. The 

 bone is thin and finely striated throughout. 



30. Cret. Yon. Weet., pi. XL. fig. 7. 

 M. Paleontograpliica, 1*1*2. p, 117. 



