I903-] 



Hay, North American Cretaceous Fishes. 



7 



and some other fishes. Intermuscular bones are well de- 

 veloped, those arising just behind the head being especially 

 long and slender. 



Some scales are present. One is i8 mm. long and 5 mm. 

 wide. The exposed portion is marked with lines radiating 

 from the centre of growth. 



Cope has described the form of the upper surface of the 

 skull. It presents three planes, a median and two lateral. 

 The median is narrow at the supraoccipital, but increases in 

 width to the snout. The lateral planes are widest behind 

 and narrow anteriorly. They slope off at an angle of about 

 30° with the median 

 plane. The sides of the 

 head are about vertical. 



The bones of the upper 

 surface of the skull in 

 front of the orbits have 

 been damaged. A por- 

 tion of the frontals is 

 gone, but the imprint of 

 these and some splinters 

 ofthe bones remain. Their 

 anterior border cannot 

 be determined exactly. 

 The anterior extremity 

 of the ethmoid is present 

 and is thick and broad, 

 as seen at the upper end 

 of Fig. 23. Cope re- 

 garded this bone as the 

 consolidated premaxil- 



laries and thought that Ty^^?:^&eadfrrfb:;:'^;^;:,?rrtkif;.Tpi-r 



little if any of the ethmoid '^hl^^^^^A. -p---p-' = - -- ^ - 

 was exposed. The im- 

 print of the premaxillae and splinters of these bones still 

 remain on the upper surface of the snout on a portion of the 

 matrix which overlies the ethmoid. Again, a smooth articular 

 surface is found at the proximal end of each of the maxillae 



parietal ; 



