191 



to the corresponding part in the alligator-gar, but is proportionately not so 

 thick or robust near the symphysial end. The lower surface is reticulated 

 with round meshes, and the ridges of the net are ornate with shining trans- 

 lucent tubercles. 



The dental groove exhibits the remains of a row of large teeth, of which 

 one retained exhibits the same character as those of the living gars. The 

 outer edge of the groove was also furnished with minute teeth, but the inner 

 edge exhibits no trace of these organs. 



Lepidosteus simplex. 



Some remains of a Lepidosteus, together with some fragments of a turtle- 

 shell, were collected near Washakie Station, Wyoming, by James Stevenson, 

 during Professor Hayden's exploration of 1870. The remains of the Lepidos- 

 teus consist of a mutilated basi-occipital and three succeeding vertebral cen- 

 tra, together with several small jaw-fragments and a number of large ganoid 

 scales. 



The basi-occipital and vertebral centra, represented in Fig. 18, Plate 

 XXXII, resemble in form and proportions those of alligator-gar, but arc 

 smaller. 



A tooth, represented in Fig. 26, contained in one of the jaw-fragments 

 agrees in character with the larger teeth of living gars. The outer edge of 

 the same jaw-fragment is furnished with smaller and more curved teeth of 

 the same kind. 



Figs. 31, 32 represent two lozenge-shaped scales of less breadth but thicker 

 than those of the alligator-gar. The enamel surface is Hat, smooth, and 

 highly polished, and exhibits no markings except one or several minute puncta 

 near the center. 



Fig. 33 represents a similar scale, which appears to be traversed fore and 

 aft by a canal communicating by a short cleft with the outer surface. The 

 cleft is directed backward, and is protected by an angular elevation of the 

 anterior border. 



Fig. 34 represents another scale of a different form, probably from the 

 median line of the back. 



The measurements of the basi-occipital and vertebral centra arc as follows : 



Lines. 



Breadth of the articulation of the basi-occipital 10. 



Height from lower groove to edge of occipital foramen 5. 



Leugth of first vertebral centrum 4. 



