Stewart.] Cretaceous Fishes, 343 



ical expedition to western Kansas was fortunate enough to find 

 several good specimens from the Butte creek region of Logan 

 county, and was also loaned an almost complete specimen, the 

 tins excepted, by Mr. Travis Morse, of Tola, who secured it sev- 

 eral years ago while collecting vertebrate fossils iii this part of 

 the state. From this specimen a good idea of the anatomy can 

 be gained. 



The bone called premaxilla in the preliminary description is 

 evidently not a premaxilla, but some other bone, the location 

 of which I have been unable to determine. The premaxilla is 

 rather short, with a semiellipitical tooth band on the inferior 

 side covered with several rows of villiform teeth, all of which 

 seem to be directed inward. Above the tooth band, on the ex- 

 ternal side, there is a thin wall of bone extending upward, 

 which is covered with coarse longitudinal striae on the posterior 

 portion, while the anterior part, just behind the apex, is Cov- 

 ered with minute tooth-like tubercles, which extend backward 

 for some little distance just over the tooth band. The internal 

 side of the bone is deeply concave, the width of the concavity 

 becoming very narrow at the anterior end. The union between 

 this bone and the maxilla was no doubt very loose, allowing 

 this bone to be moved very freely. The two bones were proba- 

 bly not united anteriorly. 



The maxilla is moderately long and thin transversely toward 

 the posterior extremity. It bears a tooth band on the lower 

 border, which is slightly concave longitudinally in front, where 

 this band is the broadest. Posteriorly the tooth band gradu- 

 ally contracts in width until the two borders come together at 

 the posterior extremity. The surface for the premaxilla is 

 directed slightly inward, and in some of the specimens it is 

 slightly roughened for the ligaments binding the two bones to- 

 gether. Just back of this, on the superior border, there is an 

 elevated articular portion which serves to bind the maxilla to 

 the skull proper. It is rather rough above and does not allow 

 the free motion of the upper jaws found in some of the other 

 families of physostomous fishes. Just back of this there is a 

 thin crest of bone extending backward over one-half the length 



