SUPPOSED DESCENT OF GROUPS 283 
OF THE GROUPS OF FISHES 
observers ; their views have been based on the different lines of investigation 
interpretation of the text of the author cited. 
Balfour ('80) ui 
Gunther (’80)* 
(Ou Babryelogy and Anatomy), og) (On Anatomy) 
Ancestral Elasinobranch (On Circulatory System) Includes Lancelet and Cyclostomes 
/ as 2 Sub classes of Fishes 
Protoganoid a Palaeichthys 
of \ Bony Ganoids \ ae 
e Ganoids 
Dipnoan anoid Amphibia (With Dipnoans) 
Fyeloplares Chondrosteans 
Ceratodus (Sharks and Chimaeroids) 
Teleost 
Gill (95) 
(On Structural Characters) 
Davidoff (80) 
-------Pleuracanthid (On Extremities and Girdles) 
2 * Primitive Gnathosteme 
Dipnoan ! ! 
Chimaeroid Elasmobranch Scaphyrhynchus 
Selachian - 
Bridge (78) Acipenser -——— 
(On of Ganoids) | Shark Rays(!) 
Heptanchus —Acanthias 
Apneumato-—} | 
) 
Es emer aad Polypterus 
Elasmobranch 
| l I 
= | 
Dipnoi Physostome 
Selachoidei 
Teleosteoidei 
Rabl (’89) 
(On Embryology) 
Cyclostomes Amphioxus Pollard (’91) 
(On Anatomy of Head) 
Mears co’) | Pad 
(On Embryology and Brain) Selachians Crossopterygian 
/ | UN ed 
Selachodichthyidae Ganoids wen) = 
\ | phi 
Teleosts Amphibia Ceratodus 
and Protamuia (Trias) 
Ischyodus poe 
(ura) 
Selachians 
Protopterus 
Holocephall 
Dipnoans and 
Amphibia 
