VERTEBRATA (CHORDATA). 89 



Sub-ord. 3. Crossopterygidse. 



Fam. a. Polypteridse. Polypterus, CalamoichtJiys. 



Fam. b. ^Ccelacanthidae. Ccelacanthus. 



Fam. c. ' n TJiombodipteridse. Glyptolcemus, Osteolepis, 



Fam. d. """Cyclodipteridse. Tristichopterus. 



Fam. e. ^Holoptychiidae. Holoptychius. 



Fam. f. """Phaneropleuridse. Phaneropleuron. 



Sub-ord. 4. '""Acanthophori. 



Fam. Acanthodidse. Acanthodes. 

 Sub-ord. 5. ^Ostracostei. 



Fam. a. Cephalaspidse. Cephalaspis. 



Fam. b. Pterichtbyidse. Pterichthys. 



Sub-ord. 5. Chondrosteidse. 



Fam. a. Acipenseridse. Acipenser (Sturgeon), Scaplii- 

 rhynchus. 



Fam. b. Polyodontidse. Polyodon( = Spatularia, Paddle- 

 fish). 



(Joh. Miiller, Ueber Ganoiden und das natiirliche System der Fische, Ab- 

 handl. der Berl. Akad., 1848 ; Agassiz, Becker ches sur les Poissons fossiles, 

 1833-43 ; Huxley, Essay upon the Systematic Arrangement of the Fishes of 

 the Devonian Epoch, Mem. Geol. Survey, 1861 ; and Illustrations of the 

 Structure of the C'rossopterygian Ganoids, ibid., 1866 ; Traquair, The Ganoids 

 of the British Carboniferous Formation, Palaeontograph. Soc., 1877.) 



Fig. 80. A, Lepidosteus osseus, the " Gar-Pike " of the American Lakes ; B, Aspidorhynchus, 

 restored (after Agassiz), a Jurassic Ganoid allied to Lepidosteus, but having a homocercal 

 tail. 



