PETALODUS. 



Petalodus alleghaniensis. 



Leidy : Jour. Ac. Nat. Sc. 1856, 161, Plate XVI, Figs. 4 to ; Pr. Ac. Nat. Sc. 

 1859, 3. 



Sicarius extinctus. Leidy : Pr. Ac. Nat. Sc. 1855, 414. 



Petalodus destriictor. Newberry and Wortbeu: Geol. Sur. Illinois, vol. ii, Pal- 

 aeontology 35, Plate II, Figs. 1 to 3. St. Jobn : Hayden's Rep. Geol. Sur. 

 Nebraska, 1872, 241, Plate III, Fig. 5. 



Described page 312, and represented by Fig. 3, Plate, XVII. From the 

 Carboniferous formation of Kansas, Nebraska, Iowa, Illinois, and In- 

 diana. 



Ichthyodorulites. 



XYSTRACANTHUS. 



Xystracanhus arcuatus. 



Leidy : Pr. Ac. Nat. Sc. 1859, 3. 

 Page 312, and represented by Fig. 25, Plate XVII. From the Carbonif- 

 erous formation of Kansas. 



ASTERACANTHUS. 



ASTERACANTHUS SIDERIUS. 



Leidy : Pr. Ac. Nat, Sc. 1870, 13. 



Described page 313, and represented by Fig. 59, Plate XXXII. From 

 the sub-Carboniferous formation of Tennessee. 



Rale. 



ONCOBATIS. 



Oncobatis pentagonus. 



Leidy : Pr. Ac. Nat. Sc. 1870, 70. 

 Page 264, and represented by Figs. 18, 19, Plate XVII. From the Plio- 

 cene of Sinker Creek, Idaho. 



TRYGON. 



Trygon . 



Indicated by the basal portion of a caudal spine, represented in Figs. 54, 



55, Plate XXXII. It resembles the corresponding portion of the caudal 



spines of our common whip-sting ray, Pastinaca hastata, and would appear 



to have pertained to a species of about the same size. The anterior, shining, 

 45 g 



