CLASSIFICATION OF VERTEBRATA 



Squaloraia. Lower Lias, England. 

 Chimaeropsis and Myriacanthus. Jurassic, Europe. 

 Ischyodus, from Jurassic to upper Cretaceous, England. 

 Callorhynchus antarcticus. Southern seas ; the genus 

 known already from the lower Greensand of New 

 Zealand. 

 Chimaera monstrosa. Seas of Northern hemisphere ; 



Pliocene, Tuscany. 



[Ichthyodorylites, Buckland. Enamelled spines of the 

 dermal armour, chiefly from the dorsal fins, of various 

 fishes. 

 Onchus. Upper Silurian of Ludlow, and lower 



Devonian. 



Homacanthus. Devonian and upwards. 

 Ctenacanthus. Lower Carboniferous.] 

 IV. Division TELEOSTOMI, Bonaparte. Vertebrae 

 acentrous or arcocentrous. 

 Without mixipterygia. 



Tectobranchi, i.e. gills with one large operculum. 

 With membrane bones. Mouth terminal or subterminal. 

 Ova numerous and small. 



1. Order Crossopterygii, 1 Huxley. Paired fins lobate, 

 with a thick axis and biserial fin-rays. With a pair of jugular 

 plates. 



Osteolepis, Diplopterus. Lower Devonian, Europe. 

 Holoptychius, Glyptolepis. Devonian, Europe and 



North America. 



Megalichthys. Carboniferous, British. 

 Codacanthidae, with a large ossified air-bladder ; from 



lower Carboniferous to upper Chalk ; Undina, Jurassic ; 



Macropoma, Cretaceous. 

 Polypterus. African rivers. 

 Calamoichthys. West African rivers. 



2. Order Actinopterygii, Cope. Paired fins, with multi- 

 basal, uni-preserial ichthyopterygium. 



1 The Ganoidei of Bonaparte and most other authors comprise the present 

 Crossopterygii, Chondrostei, and Holostei. They can be defined as follows : 

 conus arteriosus with many valves ; optic nerves forming a chiasma ; with 

 intestinal spiral valve. 



