238 Dr. R. H. Traquair on the Structure 
the structure of the true Acanthodide have long since shown 
that this generalization was rather hasty. Chedrolepis, how- 
ever, he considered as forming, by the absence of spiny rays 
to the fins and by its unequal dentition, the ‘‘ passage of the 
Acanthodians to the Sauroids.” 
Although the restored figure of Chezrolepis given by Agassiz 
in the ‘ Poissons Fossiles du vieux Grés Rouge,’ tab. D. fig. 4, 
is quite erroneous as regards the shape of the maxilla and of 
the opercular bones, he having evidently supposed that the 
bones of the head were conformed much as in the recent 
Salmonide, yet as regards his assertion of the presence of 
branchiostegal rays and of an unequal dentition (facts after- 
wards questioned by others) he was undoubtedly right. 
Our own countryman Hugh Miller, however, was shrewd 
enough to be impressed with the discrepancy of structure in 
Cheirolepis and the Chetracanthé and Diplacanthi, with which 
it had been classed; and accordingly we find him, in his ‘ Old 
Red Sandstone,’ mentioning it as the type of a distinct family. 
Nor did these discrepancies escape the attention of Johannes 
Miiller, as may be seen from a brief passage in his paper 
“ Ueber den Bau und die Grenzen der Ganoiden”’*. By 
Giebel+ it was also disassociated from the Acanthodians and 
classed amongst his ‘‘ Heterocerci Monopterygu,” a group un- 
fortunately nearly as heterogeneous as Agassiz’s “ Lepidoides.” 
Nevertheless for years afterwards many eminent palzontolo- 
gists (such as Pictett, Quenstedt§, M‘Coy||, and Sir Philip 
Egerton4) continued to class Cheirolepis along with the 
Acanthodide. 
Pander, however, in one of his justly celebrated essays on 
the Devonian fishes**, entered into the structure of Chetrolepis, 
and proposed to constitute for it an independent family, the 
Cheirolepint. Many of its head- and shoulder-bones were 
* Abhandl. der Berl. Akad. 1844, Phys. K1. p. 151. 
+ ‘Fauna der Vorwelt, 1848, vol. i. p. 251. 
t ‘Traité de Paléontologie,’ 2me éd. t. ii. p.. 190. 
§ ‘Handbuch der Petrefactenkunde * (1852), p. 192. That Quenstedt 
was nevertheless rather doubtful on this point may be inferred from the 
following passage, in his description of the Acanthodide :—“ Nur Chei- 
rolepis hat Fulera an allen Flossen, und auf dem Riicken des Schwanzes ; 
dennoch halt ihn Agassiz auch fiir einen Acanthodier. Mogen auch alle 
diese Fische (ausser Chetrolepis) den lebenden Haien sich nicht unmittelbar 
anschliessen, so stehen sie ihnen doch gewiss naher als den folgenden 
Ganoiden.” 
|| ‘Paleozoic Fossils,’ p. 580. 
4 “Remarks on the Nomenclature of the Devonian Fishes,” Quart. 
Journ. Geol. Soc. xvi. p. 125. 
** ‘Ueber die Saurodipterinen, Dendrodonten, Glyptolepiden, und Chei- 
rolepiden des deyonischen Systems,’ St. Petersburg, 1860, pp. 69-73. 
