Dinichthys halmodeus (Clarke) 



Page 126 



7 Dorsomedian plate. Natural size. Superficial ornament partially 



denuded, and inferior carina exposed. 

 Marcellus shale, Livonia salt shaft, N. Y. 

 The original, found in natural association with the type cranium, is 



preserved with it in the New York State Museum. 

 Machaeracanthus longaevus sp. nov 



8 Right and left pectoral fin spines preserved in natural association. 



X 7^, Cross-sections of middle portion of either spine shown at 



the sides. 

 Trilobite bed of the Lower Hamilton, shore of Lake Erie near mouth 



of Eighteen Mile creek 

 Original in Buffalo Society of Natural History 

 199 



