﻿ICHTHYOTKlftTTTJTES. 110 



Apateacanthus vetustus (Clarke). 



1885. Pristacanthus vetustus, J. M. Clarke, Bull. U.S. Geol. Surv. 

 no. 16, p. 42, pi. i. fig. 7. 



Type. National Museum, "Washington. 



The type species. Known only by the type specimen, which is very 

 suggestive of a Chimseroid dorsal fin-spine, and certainly pertains to 

 a hitherto unrecognized genus, as already suggested by J. S. New- 

 berry, Palseoz. Pishes N. America (Mon. U.S. Geol. Surv. no. xvi. 

 1889, p. 61). 



Form. 6f Log. Upper Devonian (Naples Shales) : Yates Co., New 

 York. 



Not represented in the Collection. 



Genus PRISTACANTHUS, Agassiz. 



[Poiss. Poss. vol. iii. 1837, p. 35.] 



Spine very long, slender, and gradually tapering, extremely com- 

 pressed laterally, with acute anterior and posterior margins ; sides 

 smooth, a longitudinal band of gano-dentine covering the anterior 

 half ; a single series of large, compressed, triangular denticles upon 

 the posterior margin. 



Pristacanthus securis, Agassiz. 



1825. " Defense caudale," E. Deslongchanips, Mem. Soc. Linn. Nor- 



mandie, vol. ii. p. 271, figs. 1-3. 

 1837. Pristacanthus securis, L. Agassiz, Poiss. Foss. vol. iii. p. 35, 



pi. viii. a. figs. 11-13. 

 1871. Prist acatithus securis, J. Phillips, Geol. Oxford, p. 178, diagr, 



xxxviii. fig. 10. 

 1890. Pristacanthus securis, A. S. Woodward, Proc. Geol. Assoc, vol. xi. 



p. 290, pi. iii. fig. 2. 



Type. Caen Museum, and Royal College of Surgeons, London. 

 The type species. 



Form. &f Log. Great Oolite : Caen, Normandy. Stonesfield Slate : 

 near Oxford. 



P. 6253. Crushed specimen showing internal cavity; Allemagne, 

 near Caen. Purchased. 



32726-27. Two specimens, one showing the imperfect tapering 

 distal portion, the other exhibiting the characteristic lateral 

 band of gano-dentine ; Allemagne. Tesson Coll. 



41306. Imperfect distal portion of spine ; Allemagne. 



Purchased, 1869. 



