CESTRACIONTIDiE. 
279 
Genus ACRODUS, Agassiz. 
[Poiss. Foss. yoI. iii. 1838, p. 139.] 
Syn. Sphenonchus , L. Agassiz, tom. cit. 1843, p. 201 (in part). 
Thectodus, Meyer & Plieninger, Beitr. Pal. Wiirttembergs, 1844, 
p. 116. 
A genus only differing from Hybodus in the rounded, non-cuspidate 
character of the teeth. 
As in the case of Hybodus, the species are arranged in stratigra- 
phical order; and all determinations of dorsal fin-spines must be 
regarded as provisional. 
Acrodus gaillardoti, Agassiz. 
1837. Acrodus gaillardoti, H. B. Geinitz (ex Agassiz, MS.), Beitr. 
Kennt. Thiiring. Muschelkgeb. p. 21, pi. iii. fig. 5. 
1839. Acrodus gaillardoti, L. Agassiz, Poiss. Foss. vol. iii. p. 146, 
pi. xxii. figs. 16-20. 
1839. Acrodus braunii, L. Agassiz, tom. cit. p. 147, pi. xxii. fig. 26. ' 
1849. Acrodus gaillardoti, H. von Meyer, Palseontogr. vol. i. p. 229, 
pi. xxviii. tigs. 3-8, 12, 13. 
1849. Acrodus braunii, H. von Meyer, loc. cit. p. 231, pi. xxviii. 
figs. 1, 2. 
1852. Acrodus gaillardoti, P. Gervais, Zool. et Pal. Fran^., Explic. PI. 
Poissons Foss. p. 13, pi. lxxvii. fig. 14. 
1856. Acrodus gaillardoti , C. Giebel, Zeitschr. gesammt. Naturw. 
vol. viii. p. 428. 
1857. Acrodus gaillardoti, C. Chop, Zeitschr. gesammt. Naturw. vol. ix. 
p. 130. 
(P) 1859. Acrodus gaillardoti, K. von Schauroth, Sitzungsb. k. Akad. 
M iss. math.-naturw. Cl. vol. xxxiv. p. 350, pi. iii. fig. 21. 
1861. Acrodus gaillardoti, E. E. Schmid, Nova Acta Acad. Cass. Leop.- 
Car. vol. xxix. no. 9, p. 16, pi. ii. figs. 29-32. 
1865. Aei'odus gaillardoti, H. Eck, Form. bunt. Sandst. u. Muschelk. 
Obersclilesien, p. 116. 
1870. Acrodus gaillardoti, F. Boemer, Geol. von Obersclilesien, pi. xih 
fig. 10. 
1880. Acrodus gaillardoti, T. C. TVinkler, Archiv. Mus. Teyler, vol. v» 
livr. 2, p. 109, pi. v. figs. 1-3. 
1883. Acrodus gaillardoti, H. E. Sauvage, Bull. Soc. Geol. France, [3] 
vol. xi. p. 494, pi. xii. fig. 4. 
Type. Detached teeth. 
A species of moderate size, the principal teeth not measuring 
more than 0*035 in length, gently rounded, marked by numerous 
fine branching and bifurcating wrinkles. Anterior teeth slightly 
keeled, not much elevated. 
