488 FISHES CHAP, 
features, and they flourished in large numbers during the Carbo- 
niferous and Permian periods. Platysomus ranges from the 
Lower Carboniferous to the Upper Permian in Great Britain 
and continental Europe, and also occurs in the Carboniferous 
of North America. Hurynotus (Fig. 285), and the singularly 
deep-bodied Cheirodus (Fig. 286), in which pelvic fins are 
unknown, are British Carboniferous genera. 
ds 50 J 
dect Linn 
HY fi q 
aaa 
Fia. 286.—Restoration of Cheirodus granulosus. d.ect, Dermal lateral ethmoid ; d.eth, 
dermal mesethmoid ; d.sp, either a dermal sphenotic or a post-orbital bone ; /./, 
lateral line; orb, orbit. The pectoral fin is indicated in dotted outline. Other 
reference letters as in Fig. 284. (From Traquair.) 
Fam. 3. Belonorhynchidae.—The systematic position of 
these Triassic forms is very doubtful, and it is by no means 
clear that they are Chondrostei at all. 
Fam. 4. Catopteridae.—It is very probable that this widely- 
distributed Triassic family is an offshoot from the Palaeoniscidae. 
It agrees with the latter in the general character of the head 
and pectoral girdle and in the rhombic squamation, but differs 
from its progenitors and approaches the more modern Holostei 
in the semi-heterocercal condition of the tail, and in the approxi- 
mate numerical agreement between the fin-rays and radialia of 
the dorsal and anal fins.’ 
* Smith Woodward, Brit. Mus. Cat. Foss. Fishes, iii. 1875, p. 7. 
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