746 THE AMYZON BEDS. 



skull remains. A second consists of the entire cranium ; a third, of the 

 tail ; and a fourth, of a specimen in good condition, lacking head and tail. 



The first-mentioned specimen shows that there are ten or twelve rows 

 of scales above the vertebrae, and that the dorsal fin commences about an 

 inch behind the line of the posterior border of the cranium. It also exhibits 

 the strong sculpture of the surfaces of the latter to consist of narrow inos- 

 culating ridges, inclosing large and smaller pit-areas. 



The specimen exhibits this sculpture to be very marked on the oper- 

 cular, suborbital, parietal, frontal, and sublingual bones, the only ones 

 where it displays the surface The branchiostegal radii number twelve, 

 the upper large and wide. The subopercular is turned up anteriorly as in 

 A. calva, and is thickened on the border of the suture with the interoper- 

 culum. The sublingual bone has much the form of that of A. calva, but is 

 rather wider, and then more abruptly contracted than in a specimen of 

 the latter before me. The orbit is smaller relatively than in A. calva. 



It is uncertain whether this and the preceding species possessed the 

 dentition of Amia or Pappiclitliys Cope, as the mandibular bone is partially 

 and abruptly contracted near the apex, so the teeth may belong to the 

 inner row of the true Amia, which is wanting in Pappichthys. 



The fourth specimen displays the ventral fins and the characteristic 

 femoral supports. The fins originate about an inch behind the line of origin 

 of the dorsal fin in a specimen of 0".055 depth of body. The scales 

 exhibit also the dermal margin with truncate posterior outlines seen in the 

 existing species ; this character is chiefly seen on the abdominal sui-faces. 

 There are thirty-five vertebrse between vertical lines drawn from the 

 beginning of the dorsal fin and end of the basis of the anal fin, and thirty- 

 two dorsal radii in the same interval ; anal radii, nine ; vertrals, six. 



Measurements. 



M. 



Depth of body to veitebrie (No. 1) 0.045 



Length of four dorsal vertebrse (No. 1) 019 



Depth of one dorsal vertebra (No. 1) 010 



Length of head to free border of operculum (No. 2). 124 



Depth of operculum of do 032 



Length of head on vortex "093 



Length from end of muzzle to orbit 032 



Length of orbit 012 



From South Park, Colorado. 



