148 



TELE OS TOMES 



reduced, implanted with- 

 in body wall. Includes 

 Chondrosteans (" Gan- 

 oids ") and Teleocephali 

 ("Teleosts"). 



I. CROSSOPTERYGIANS 



The CROSSOPTERYG- 

 IANS, as palaeontology 

 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. 



Polyp tents (Figs. 148, 

 A,B, 149) and its kindred 

 genus, CalamoichtJiys 

 (Fig. 150), stand alone 

 as the survivors of the 

 Crossopterygian group. 

 They have diverged but 

 little from their Devo- 

 nian kindred, and demon- 

 Fig. 148. The Nile bichir, Polypterus strate j n the most inter- 

 frickir. X J. White Nile. (Modified after 



L. AGASSIZ.) estins; way the persistent 



A. Dorsal aspect. B. View of throat re- 

 gion, showing jugular (gular) plates and ven- survival of fishes. From 

 tral elements of the dermal shoulder girdle. 



