Ctenoptychius, Ctenopetalus, and Harpacodus, 425 
genus Otenoptychius and redescribed the species C. apicalis, 
Ag., including therein C. apicalis, Ag. (Binney, Trans. 
Manch. Geol. Soe. vol. i. t. 5. fig. 19), Petalodus dentatus, 
Owen (Odont. p. 62), and C. macrodus, Ag. ined. (and 
Portl. Geol. Rep. t. 14. fig. 7). A second species is described, 
C. serratus, Ow.? (Owen, Odontog. p. 62), and figured on 
pl. 31. figs. 21, 22, 23. During 1858 Prot. Agassiz visited 
the Harl of Enniskillen at Florence Court, and revised his 
genus Ctenoptychius. He divided it into three genera. C. 
apicalis being taken as the type of the old genus, C. serratus 
forms the type of a new genus Céenopetalus, and C. dentatus 
the type of the third genus Harpacodus. 
Since Prof. Agassiz made these determinations many addi- 
tions have been made to the species, both in this country and 
more especially in America, and the whole group has reached 
a state of considerable confusion. It was the intention of 
Prof. Agassiz to greatly amend and rewrite his work on 
the fish-palates of the Mountain Limestone; but the great 
pressure of engagements in connexion with his labours in 
America prevented, from time to time, this being accomplished; 
and by his premature death all chance of its being done has 
been cut off. The work has been rendered comparatively easy, 
however, by the careful determinations of Agassiz and the 
knowledge possessed by Lord Enniskillen of his intentions 
with regard to them, as well as from the fact that all the type 
specimens are in the Florence-Court collection. 
The following descriptions of the genera are derived prin- 
cipally from a study of the type specimens. The enumeration 
of species appended to each may be taken as suggestive rather 
than any thing else. 
Genus CTENOPTYCHIUS, Agass. ined. 
Gen. char. Teeth small; crown strongly compressed, 
more or less acuminate and often irregular in form; cutting- 
edge divided into several strong denticulations, the central 
one largest and most prominent; base of crown with a few 
imbricating folds of ganoine ; bony root thin, flattened in the 
same direction as, and longer than, the crown. 
Ctenoptychius apicalis, Agass. Poiss. Foss. t. ii. p. 99, pl. xix. 
figs. 1, la. (Type.) s 
C. pectinatus, Ag. P. Foss. WOK it, Jo. DOO, Galle xab<; ten. 4! 
only). 
C. ae St. J. & W. Paleont. Illin. vol. vi. p. 382, pl. x. a. 
fig. 27. 
Ann. & Mag. N. Hist. Ser. 5. Vol. viii. 30 
