DEVONIC FISHES OF THE NEW YORK FORMATIONS 85 



tudinal sulci, separated by narrow ridges, which terminate before reaching 

 the distal three fourths of the spine. 



Regarding the distribution of this species, Newberry offers the follow- 

 ing remarks : 



It would seem that the sharks that carried these spines were more 

 numerous in those portions of the Corniferous sea which covered western 

 New York and southern Canada than in the more open waters of the area 

 now occupied by Ohio. In the exposures of the Corniferous limestone on 

 Kelly's island, Lake Erie, at Sandusky, Delaware and Columbus, O., frag- 

 ments or complete spines of Machaeracanthus major and M. p e r a- 

 c u t u s are not at all uncommon, but though collecting extensively myself 

 in those localities I never obtained there a specimen of M. s u 1 c a t u s. 



Formation and locality. Onondaga limestone (Ulsterian) ; various 

 places in New York State and Canada, and in the corresponding horizon 

 at Milford, O. 



Machaeracanthus longaevus sp. nov. 



Plate 2, figure 8 



Spines attaining considerably larger dimensions than the type and 

 differing principally in their greater width and conformation of the median 

 carina. The latter is sharply triangular on one side in the distal portion 

 only of the spine, gradually becoming widened and flattened until in the 

 proximal portion it is nearly rectangular in cross-section. No longitudinal 

 sulci. 



This species, the only one known to persist as late as the Hamilton, is 

 founded upon an interesting specimen belonging to the Buffalo Society of 

 Natural Sciences, and derived from the so called " Trilobite bed " on the 

 shore of Lake Erie near Eighteen Mile creek. New York. It was kindly 

 placed in the hands of the writer for description by its discoverer, Mr F. K. 

 Mixer, of Buffalo. Portions of two spines are preserved in counterpart on 

 the same slab, embedded in which are pygidia of Phacops ran a, and 

 tests of Spirifer mucronatus and Ambocoelia umbonata, 

 characteristic fossils of the Hamilton beds. 



The present example is interesting in that it is one of the few in which 

 spines of both pectoral fins are preserved in natural association. That this 



