METAZOA CHORDATA. 



I Eiuheria, Placentals. 

 Mammalia. -/ Metatheria. Marsupials. Non-pla- 

 j cental. 



\ Prototheria. Monotremes. Oviparous. 



( Carinatae. Keeled flying birds. 

 AVES. 4 Ratitae. Keel-less running birds. 



\ Saururae. Extinct reptile-like birds. 



ICrocodilia. Crocodiles and alligators. 

 Ophidia. Snakes. 

 Lacertilia. Lizards. 

 Proterosauria. Sfhenodon. 

 Chelonia. 'lortoisesand turtles. 



, Anura. Tail-less frogs and toads. 



) Urodela. Tailed newts. 

 Amphibia. -l Gymnophiona, e.g.^ Cecilia. 



I Labyrinthodonts and other extinct 

 amphibians. 



I Dipnoi. ^ Mud-fishes. 

 Pisces. \ Teleostei. Bony fishes. 



j Ganoidei, e.g.^ Sturgeon. 



\ Elasmobranchii. Cartilaghious fishes.^ 



CvcLOSTOMATA. -f ^^^^^ iMyxine\ and Lamprey 

 \ \FetroiHyzon), 



Cephalochordata. Amphioxus. 



Urochordata. Tunicates. 



Hemichordata. Balanoglosstts an4 Cephalodlscus. 



METAZOA NON-CHORDATA. 



3S 



^O 



% 



5:0 





Mollusca. 



Arthropoda. 



echinoder- 

 mata. 



{Cephalopoda. Cuttle-fishes. 

 Gasteropoda. Snails. 

 Lamellibranchiata. Bivalves. 





Arachnoidea. Spiders, scorpions, mites. 



Insecta. 

 i Myriopoda. Centipedes and millipedes. 

 \ Protracheata. Peripatiis. 

 ^ Crustacea. 



ICrinoidea. Feather-stars. (Cystoids and Blastoids, extinct.) 

 Ophluroidea. Brittle-stars. 

 Asteroidea. Star-fish. 

 Echinoidea. Sea-urchins. 

 Holothuroidea. Sea-cucumbers. 



' Worms." 



( Brachiopoda. Lamp-shells. 



I Polyzoa, e.g.^ Sea-mat {Fius^rd). 



( Sipunculoidea, e.g., Sipunculus. 



S Chaetopoda. Bristle-footed worms. ) . vj 

 JDiscophora. Leeches. j-Annehds. 



Nematoda. Thread-worms. 

 Nemertea. Ribbon-worms. 



( Cestoda. Tape-worms. \ 



I Trematoda. Flukes. rPlathelminthes. 



( Turbellaria. Planarians. ) 



(Ctenophora, e.g., Beroe. 

 Scyphozoa. Jellyfish and sea-anemones. 

 Hydrozoa. Zoophytes and medusoids. 



PoRiFERA. Sponges. 



PROTOZOA. 



Infusoria. Rhizopoda. Gregarinida. 



Simplest forms of animal life. 



