Fig. 148.—The Nile bichir, Polypterus 
bichir. X%. White Nile. (Modified after 
L. AGASSIZ.) 
A. Dorsal aspect. 2. View of throat re- 
gion, showing jugular (gular) plates and ven- 
tral elements of the derma! shoulder girdle. 
TELEOSTOMES 
reduced, implanted with- 
in body wall. Includes 
Chondrosteans (“ Gan- 
oids”) and Teleocephalé 
(“ Teleosts ”). 
I, CROSSOPTERYGIANS 
The CROsSSOPTERYG- 
IANS, as_ palzontology 
has demonstrated, are 
the most ancient Tele- 
ostomes. In their struct- 
ural characters — espe- 
cially in the fins, skeleton, — 
nervous system —they 
are clearly to be sepa- 
rated from the neigh- 
bouring Ganoids. And 
their transitional charac- 
ters have not as yet been 
clearly demonstrated. 
Polypterus (Figs. 148, 
A, B, 149) and its kindred 
genus, Calamoichthys 
(Fig. 150), stand alone 
as the survivors of the 
Crossopterygian group. 
They have diverged but 
little from their Devo- 
nian kindred, and demon- 
strate in the most inter- 
esting way the persistent 
survival of fishes. From 
