227 



premaxillary teeth from the outer row. The external lamina of the premax- 

 illary forms an extensive squamosal suture with this part of the maxillary by 

 overlapping it from above. This arrangement shows a certain similarity to 

 Esox, especially in the large number of palatine and small number of max- 

 illary teeth. It differs materially in the lack of articular surfaces between 

 the maxillary, palatine, etc., in the upward prolongation of the premaxillary, 

 and the peculiar forms of the teeth. 



Stkatodus apicalis, Cope. 



Established on one incomplete individual, as above mentioned. 



The maxillary teeth are mostly smaller than the premaxillaries, and 

 diminish in size posteriorly ; there are four or five series of them anteriorly ; 

 seven to nine rows on the palatine bones ; they are slender, and curved down- 

 ward from oblique bases, and cylindric in section; they contract to a neck, 

 and then expand into the ovate spade-shaped cutting apex. They are in every 

 respect the largest of the teeth, some reaching a half-inch in length. Those 

 on the inferior or outer margin are most slender; those of the inner stouter 

 and more conic. All the spade-like apices are black in the specimen, while 

 the shanks are pale, except the premaxillaries. The palatine bones are flat- 

 tened in one plane, and contracted at both ends. At the anterior, there is an 

 external concavity, perhaps for maxillary or premaxillary. A ridge divides 

 the upper surface lengthwise ; the outer edge is thinned posteriorly, and there 

 are three long grooves which extend to the posterior extremity, probably for 

 sutural union with the pterygoid. The premaxillary bears a slight resem- 

 blance to the mandibular bone of a chimeroid turned upside down. 



Measurements. 



M. 



Length of a portion of an os palatinum 0. 12S 



Length of same restored 0. 148 



Greatest width 0.020 



Greatest thickness on the margin 0. 003 



Lsngth of the premaxillary (fragment) 0. 043 



Length of the premaxillary, inner side 0. 025 



Length of the premaxillary, outer side to the maxillary 0.012 



Width of the premaxillary in front above 0. 010 



Length of a premaxillary tooth 0. 005 



This fish was considerably larger than Esox reticulatus or E. lucius. In 

 the lack of mandible, its habits cannot be fully inferred; but the armature of 

 the superior bones of the mouth is less powerful, relatively, than in those 

 fishes. 



Found by myself in the blue limestone near Fort Wallace. 



