512 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
Ctenoptychius, which are still included in the genus, are from the Coal Measures : 
so far as at present known the genus Ctenoptychius is not represented during the 
Carboniferous Limestone period. In 1859. Prof. Agassiz revised the group and 
made the above-named species form the types of new genera. ‘These genera have 
not hitherto been described, but the types have remained in the collection at 
Florence Court. Professor Agassiz, in the “ Poissons Fossiles,” considered that the 
Ctenoptychians present a great resemblance to an Orodont squeezed flat. Their 
general form, however, is without doubt nearly related to the Petalodonts. The 
convex surface of the anterior face of the crown and the concave surface behind, 
form avery near resemblance to the petal-shaped tooth of Petalodus ; they are 
distinguished by the deeply denticulated or pectinated cutting surface. ‘‘ Whilst 
agreeing in the possession of a family likeness one with the other, they exhibit con- 
siderable generic distinctions. The genus Harpacodus differs from the other two in 
its thick, strong crown, and the almost straight contour formed by the enamelled 
tips of its denticles. The constricted, tumid, and prominent bony base is quite 
different from the flattened bases of Ctenopetalus and Ctenoptychius. The denti- 
culation of the three genera is sufficiently distinct. Ctenoptychius, though pos- 
sessing about an equal number of denticles with Harpacodus, is distinguished by 
their peculiar irregularly accuminate arrangement, whilst in Harpacodus they 
extend almost in a straight line across the tooth. The denticulation of Ctenopetalus 
is easily discriminated by the large number of denticles and their comparative 
smallness in proportion to the size of the tooth.” 
Ctenopetalus serratus, Agass. MSs. 
(RINT Xaeites s65Gan/eucs) 
Ctenoptychius serratus—L. Agassiz, 1833. . “ Rech. s. 1. Poiss. Foss,” Vol. IIT., pp. 173, 383. 
Petalodus 1 R. Owen, 1840. “ Odontograpiy,” p. 62. 
Ctenoptychius _,, J. E. Portlock, 1843, ‘Geol. Rept. on Londonderry,” &e., p. 461. 
7 - C. G. Giebel, 1848. ‘Fauna der Vorwelt,” Vol. L, pt. 3, p. 345. 
5 5 H. G. Bronn, 1848. “ Nomencl. Paleont.,” p. 356. 
59 5 3 1849. ‘ Enumerator Paleont.,” p. 646. 
3 ~ J. Morris, 1854. “Cat. Brit. Foss.,” p. 324. 
s 5 He Je Pictet; 1854. <“Traité de Paléont.,” Vol. IL., p. 264. 
9p on F. M‘Coy, 1855. “Brit. Paleeoz. Foss.,” p. 626, pl. 3 I, figs. 21, 22, 23. 
% pectinatus—E. W. Binney, 1855. “Trans, Manchester Geol. Soc,” Vol. I., pl. v., 
figs, 20, 21. 
Ctenopetalus serratus—L. Agassiz, 1859 ‘ Enniskillen Coll. MSS.” 
i ) Morris & Roberts, 1862. “ Quart. Journ. Geol. Soc.,” Vol. XVIII, p. 101. 
ts ‘, Enniskillen, 1869. ‘Cat. Type Specimens,” p. 4. 
Ctenoptychius __,, Young & Armstrong, 1871. “Trans. Geol. Soc. Glasgow,” Vol. IIL, Supt., p. 71. 
Ctenopetalus >» eat Seen ; 1876. “ Catal. W. Scot. Foss.” p. 61. Li 
» »» J. J. Bigsby, 1878. ‘“ Thes. Devon.-Carb.,” p. 353. 
Ctenoptychius _,, ¥ mi = 4 p. 398, 
Ctenopetalus in J. W. Davis, 1881. “Ann. and Mag. Nat. Hist.,” p. 626. 
