DEVONIC FISHES OF THE NEW YORK FORMATIONS 83 



indicated by one rather large spine preserved in the State Museum at 

 Albany, from western New York. 



Formation and locality. Hamilton limestone (Erian) ; Milwaukee, Wis. 

 Cedar Valley limestone and State Quarry beds ; Iowa. Portage shale 

 (Senecan) ; New York. 



Heteracanthus uddeni Lindahl 



1897 Heteracanthus uddeni J. S. Lindahl. Cinn. Soc. Nat. Hist. Jour. 

 19:9s, pi. 6 



1898 Heteracanthus uddeni C. R. Sastman. Am. Nat. 32:557 



1899 Heteracanthus uddeni C. Ji. £astman. Jour. Geol. 7 : 282 



Spines of moderate size having the distal portion essentially as in the 

 preceding species, but the basal portion curving forward so as to form a 

 rounded anterior projection or "shoulder," somewhat similar to that in 

 Stethacanthus. The longitudinal costae are finer and more closely crowded 

 than in the type species, and exhibit a sigmoidal curvature toward the base. 



Formation and locality. Cedar Valley limestone (Mesodevonic) ; Buf- 

 falo, Waterloo and Waverly, la. Hamilton limestone (Erian) ; Milwaukee, 



Wis. 



Genus machaeracanthus Newberry 



Syn. Machaerius Roualt ; Dinacanthodes Fritsch 



Spines, so far as known, elongated, tapering, more or less curved, and 

 somewhat laterally compressed, with sharp edges and a very large longi- 

 tudinal ridge on each side ; central cavity extending nearly to the apex ; 

 external surface covered with a thin layer of ganodentine, smooth, finely 

 punctate, or longitudinally striated. 



The resemblance between the spines referred to this genus and those 

 occurring in advance of the pectoral fins in Acanthodes, together with the 

 fact that the proximal portion indicates a corresponding position, has been 

 interpreted as pointing to Acanthodian afifinities. 



