ICHTHYODOTtFLTTES. 
119 
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. Fishes N. America (Mon. U.S. Geol. Surv. no. xvi. 
1889, p. 61). 
Form. Sf Log. Upper Devonian (Naples Shales) : Yates Co., New 
York. 
Not represented in the Collection. 
Genus PRIST ACANTHUS, Agassiz. 
[Poiss. Boss. 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. Deslongchamps, 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. Pristacanthus 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 Eoyal College of Surgeons, London. 
The type species. 
Form. Sf 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. 
