358 On the Age of the Sandstones of the Newark Group. 
was founded upon a careful comparison of the genus Catopterus 
with the fossil fishes of different formations in Kurope, as these 
are portrayed in the great work of Prof. Agassiz, then recent] 
received. Such portion of the description and observations 
then made as relate directly to the geological age of the forma- 
tion are here quoted. : : 
Of the genus Cutopterus, species C. gracilis, he says:—“ Tail 
forked, equilobed.. Scales extending a little upon the base of 
the upper lobe.” And in regard to the equilobed tail, he adds 
in a subjoined note:—‘ This indeed is not strictly the case. Its 
structure, however, is analogous to that of the Semionotus 
ranked by iz among the Homocerci, and differs most deci- 
dedly from that of the true Heterocerci, where the scales, and 
robably the a extend to the extreme point of the upper 
obe. e adds :— 
“Tn the arrangement of Agassiz, this fish would be compre- 
hended in the order Ganoides, and family Lepidoides. Its equi- 
lobed tail would assign it to the second division of the family, 
the Homocerci, as he has termed them. From seven fusiform 
genera now arranged in this division it is entirely excluded by 
the posterior position of its dorsal. It may therefore be rank 
between the genera Semionotus and Pholidophorus, being analo- 
gous to both in the structure of the tail, and in its serrated fins, 
and to the latter in the articulation of the rays. From the situ- 
ation of the dorsal fin I have thought the name Catopterus to be 
mga to this new genus.”—Annals Lyc. Nat. Hist. vol. iv, 
pp. . 
Nearly twenty years have elapsed since the promulgation of 
these careful and apparently conclusive observations, which do 
not appear to have been weakened or set aside by any subse- 
quent researches. It is proper to state that the two analogous 
genera above mentioned are found in the Oolitic series as wel! a8 
in the Lias, and it is believed that few, if any of the kindred 
hand, it appears to be admitted that the true heterocerques, of the Palaoniscus 
ss 8 do not appear above the Trias, and I think they are not found above the Per- 
It should be noted that Sir. P. Egerton has described a most singular fish from 
the upper strata of the New Red, of a genus hitherto unknown, which has but little 
uality in the structure of its caudal base. ‘This fish, the Dipteronotus cyp 
Eg,, is very short and broad, with a double dorsal, and is altogether so unigue in its 
character that its occurrence may be deemed to affect but little the chronological 
peptic which are drawn from the varied structure of the numerous genera and 
species of the Lepidoid family —See Geol. Jour. 1854, p. 869, with a figure. 
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