DEVONIC FISHES OF THE NEW YORK FORMATIONS 117 



Genus acanthaspis Newberry 

 An imperfectly definable genus of Coccostean fishes, known only by 

 detached plates resembling the antero-ventrolaterals of Phlyctaenaspis. 



Acanthaspis armata Newberry 



Plate 2, figure 2 



1875 Acanthaspis a r m a t u s /. .S'. Newberry. Geol. Sur. O. Rep't. Pal. v. 2, 



pt 2, p. 37, pi. 53, fig. 1-6 

 1889 Acanthaspis a r m a t u s J. S. Neivberrv. U S. Geol. Sur. Monogr. 16: 36, 



pl- 31 

 1894 Acanthaspis armata R. H. Traqualr. Ann. Mag. Nat. Hist. ser. 6, 



14:371 

 1896 Acanthaspis armata E. W. Claypole. Am. Geol. 17:354 



The spiniferous plates which are known under this provisional designa- 

 tion have not been found in natural assemblage with other parts of the 

 skeleton of forms accompanying them in the same formation, hence their 

 precise relations are indeterminable. Theoretical associations are for the 

 most part valueless, except as they rest upon strongest possible presumptive 

 evidence ; and in the present case sufficient data for comparison is lacking. 

 The superficial ornament somewhat resembles that of Macropetalichthys, but 

 according to all appearances that genus was destitute of dermal body armor- 

 ing. For the present we are obliged to regard Acanthaspis as a provisional 

 genus, whose relations may be assumed to be in the vicinity of Phlyctae- 

 naspis, and not, as was supposed by Newberry, with any member of the 

 Cephalaspidae. 



None of the plates in question that have thus far come to light seem 

 to be preserved in their entirety, but the small specimen shown in plate 2, 

 figure 2, is perhaps as complete as any. The lateral spine is always 

 immovably attached to its supporting plate by an oblique suture, which is 

 more conspicuous in larger examples. The interior of the spinous portion is 

 hollow throughout, and along the line of its attachment with the supporting 

 plate is sometimes to be seen a double row of perforations which communi- 

 cate with the internal cavity of the spine. 



