446 CLASSIFICATION OF DEVONIAN FISHES 
modern representatives of the suborder ; Polypterus being separated 
from those members of its suborder with which it has the closest 
zoological relations, by a prodigious gulf of time, and from the 
fossil allies which are nearest to it in time, by deficient zoological 
affinity. I may make my meaning more intelligible by a diagram, 
however. 
PAL-EOZOIC. 
Ctenododipterin’, Phaneropleurini, Glyptodipterin’, Saur se ee nt, 
Celacanthine. 2 
AIESOZOIC. 
Calacanthinz, 
TERTIARY. 
RECENT. 
Lolypterine. 
Here it is obvious that, in time, the Polypterini are twice as 
remote from their immediate zoological affines, the Saurodipterini 
and Glyptodipterini, as they are from their more distant connexions, 
the Ccelacanthini. 
It seems singular that while the line of the rhombiferous Cros- 
sopterygide has so distinct a modern representative, the cycliferous 
woop oro  TEEEI LEE 
<UL Ml EH 
A 
Sf 
\ 
a 
Fig. 18. Diagram of Lepedoszren. 
Crossopterygidze seem to have died and left no issue at the end of the 
Tertiary epoch. But without wishing to lay too much stress upon 
the fact, I may draw attention to the many and singular relations 
which obtain between that wonderful and apparently isolated fish, 
Lepidosiven, sole member of its order, and the cycloid Glyptodipterine, 
Ctenododipterine, Phaneropleurine, and Ccelacanth Crossopterygide. 
Lepidostren is, in fact, the only existing fish whose pectoral and ven- 
tral members have a structure analogous to that of the acutely lobate, 
paired fins of Holoptychius, of Dipterus or of Phaneropleuron, though 
the fin rays and surface scales are still less developed in the modern 
than in the ancient fish. The endoskeleton of Lepzdosiren, again, is) 
as nearly as possible, in the same condition as that of Phaneropleuron, 
and is more nearly similar to the skeleton of the Coelacanths than that 
of any other recent fish ; while, perhaps, it is not stretching the search 
