DEVONIC FISHES OF THE NEW YORK FORMATIONS Jl 



Ptyctodus calceolus Newberry & Worthen 

 1866 Rinodiis calceolus JVc7C'/>erry &= Worthen. Pal. 111. 2: 106, pi. 10, fig. 10 

 1870 Ptyctodus calceolus Newberry &• IVort/ieii. Geol. Sur. III. Rep't, 4: 374 

 1875 Ptyctodus calceolus J. S. Newberry. .0. Geol. Sur. Rep't. v. 2, pt 2, 



P- 59, Pl- 59, fig- 13 

 1898 Ptyctodus calceolus C. R. Eastman. la. Geol. Sur. Rep't. 7:115, text 



fig. 10a 



1898 Ptyctodus calceolus C. R. Eastman. Am. Nat. 32 : 476, fig. 1-17 



1899 Ptyctodus calceolus 6". Welter. Jour. Geol. 7 : 484 



Dental plates compressed into a thin cutting edge shortly behind the 

 symphysis, but widening gradually, becoming more or less outwardly 

 curved, and the oral surface occupied for nearly its entire width by the 

 tritoral area, the inner margin of which is more strongly curved than the 

 other. Laminar structure of the tritors indicated superficially by fine 

 punctae arranged in parallel rows running obliquely across the functional 

 surface. The compressed edge in advance of the tritor in the lower dental 

 plate slopes rapidly upward and terminates in a strong anterior beak. 

 Upper dental plates similar to the lower, except that the symphysial border 

 is rounded and not produced into a beak. 



In spite of the extraordinary abundance of this species in various Mid- 

 dle and Upper Devonic localities, as indicated by detached tritors, complete 

 dental plates are very rare, their structure being on the whole very fragile. 

 Of widespread distribution in the Hamilton, the species is most prolific in 

 the Upper Devonic State Quarry beds near Iowa City, a single exposure 

 only a few yards square having yielded thousands of abraded tritors. No 

 specimens have been hitherto reported from New York State, nor has the 

 genus itself been known to occur in rocks of earlier age than the Hamilton 

 in this country. Recently, however, the writer has had the opportunity of 

 examining a nearly perfect lower dental plate, evidently of this species, 

 which was collected by Mr Edgar E. Teller from the Genesee shale at 

 Eighteen Mile creek, near Buffalo. The precise level at which this dental 

 plate was found is from near the base of the Conodont bed, the exposure 



