VERTEBRATES. 237 



Plysonemus parvulus ST. JOHN & WORTHKN. 



Plysonemus parvulus St. John & Worthen, 1875: Geol. Sur. Illinois, vol. 

 VI, p. 453, pi. xvhi, fig. lla. 



Horizon and localities. Lower Carboniferous, Keokuk 

 limestone : Boonville (Cooper county). 



Drepanacanthus reversus ST. JOHN & WORTHEN. 



Drepanacanthus reversus St. John & Worthen, 1875: Geol. Sur. Illinois, vol. 



VI, p. 456, pi. xix, figs. 5, 6. 

 Drepanacanthus reversus St. John & Worthen, 1883: Geol. Sur. Illinois, 



vol. VII, p. 253, pi. xxiv, fig. 5a. 



Horizon and localities Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Erismacanthus maccoyanus ST. JOHN & WORTHKN. 



Erismacanthus macoyanus St. John & Worthen, 1875: Geol. Sur. Illinois, 

 vol. VI, p. 461, pi. xxii, figs. la-d. 



Horizon and localities. Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Amacanthus gibbosus (NE\YBERRY & WORTHEN). 



Homacanthus gibbosus Newberry & Worthen, 1866: Geol. Sur. Illinois, 



vol. II, p. 113, pi. xii, fig. 1. 

 Amacanthus gibbosus St. John & Worthen, 1875: Geol. Sur. Illinois, vol. 



VI, p. 464, pi. xxii, figs. 6a-c. 



Horizon and localities. Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Marracanthus rectus (NEWBERRY & WORTHEN). 



Homacanthus? rectus Newberry & Worthen, 1866: Geol. Sur. Illinois, vol. 



II, p. 115, pi. xii,-fig. 6. 

 Marracanthus rectus St. John & Worthen, 1875: Geol. Sur. Illinois, vol. 



VI, p. 466, pi. xxii, figs. 7a-k. 



Horizon and localities. Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Physonemus falcatus ST. JOHN & WORTHEN. 



Physonemus falcatus St. John & Worthen, 1883: Qeol. Sur. Illinois, vol. 



VII, p. 252, pi. xxiv, figs. 6a-b. 



Horizon and localities. Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



