348 CHARACTERS AND AFFINITIES OF VERTEBRA TES, 



The '"Vertebrate" Series (to be read from below up- 

 wards) — 



( CarlnatEe (flying). 

 Birds -j Ratita; (running). 



( Saururse (extinct forms). 



ACrocodilia (crocodiles, 

 etc.) 

 Ophidia (snakes). 

 Lacertilia (lizards, etc.) 

 Reptiles Rhynchocephalia — S/he- 

 nodon. 

 Chelonia (tortoises, etc.) 



Extinct Reptiles 



(many orders). 



:- V 





Sauropsida. 



Mammals. 



3, Eutheria, Placentalia, Monodel- 

 phia, the higher or placental mam- 

 mals. 



2. Metatheria, Marsupialia, _ Didel- 

 phia, Kangaroos, etc., with pre- 

 maturely born young, usually 

 nurtured in pouches. 



->- 1. Prototheria, Monotremata, Orni- 

 thodelphia, oviparous, Onii- 

 thorhynchus and Echidna. 



Mammalia. 



Amniota, embryos with amnion and allantois. 



Fishes. — Dipnoi (double breathing 



mud-fishes). 



Teleostei (modern bony 



fishes). 

 Ganoidei (sturgeon, etc.) 

 Elasmobranchii (incl. 



Holocephali), skate, 



shark, etc. 



t. 



Amphibians. 



Anura (tailless frogs, etc.) 

 Urodela (tailed newts, etc). 

 Gymnophiona (wormlike 



C(zcilia, etc.) 

 Extinct Stegocephala {_Laby- 

 rinthodon, etc ) 



Ichthyopsida (Fishes and Amphibians). 



Cyclostomata (Round-Mouths) without true jaws. 

 Myxine, hag-fish. Peiromyzon^ lamprey. 



Cephalochordata. 



Anipkioxtis^ or 

 Lancelet. 



Urochordata. — 3. Saipa type. 



Qj. 2. Ascidian type (sea- 



squirts.) 



Tunicata. i. Appendu:ularia(^2X' 



val type persistent.) 



Surviving offshoots of ancestral Vertebrates. 



Hemichordata, surviving incipient vertebrates, 

 Balanoglossus and Cephalodiscits, 



Nemertean affinities. Chaetopod affinities. Arthropod affinities 



