Invertebrates 



^1 



METAZOA NON-CHORDATA 



MOLLUSCA. 



i 



Cephalopoda. Cuttle-fishes. 



Gasteropoda. Snails. 



Lamellibranchiata. Bivalves. 



Two smaller classes : — Scaphopoda and Solenogastres. 



Arthropod.'^. 



ECHINODERMA. 



/Arachnoidea. Spiders, scorpions, mites. 



I Insecta. 



I Myriopoda. Centipedes and millipedes. 



I- Prototracheata. Peripatus. 

 Crustacea. 

 Palaeostraca : — Trilobites, Eurypterids, and King-crabs. 

 ,^Some smaller classes. 



^Crinoidea. Feather-stars. (Cystoids and Blastoids, extinct. ) 



Ophiuroidea. Brittle-stars. 

 -' Asteroidea. Star-fishes. 

 I Echinoidea. Sea-urchins. 

 V Holothuroidea. Sea-cucumbers. 



" Worms." 



Chaetopoda. Bristle worms. ^ . ,. i 

 Discophora. Leeches. I Annelids or 



Some smaller classes. / ^nnuiata. 



I" Brachiopoda. Lamp-shells. 

 I Polyzoa, e.g. Sea-mat (Flusira). 

 \ Sipunculoidea, e.g. Siptinciilus. 



Nematoda. Thread-worms. 

 Acanthocephala. 

 Nemertea. Ribbon-worms. 

 Rotifera. Wheel-animalcules. 



t Cestoda. Tape-worms. ^ 



I Trematoda. Flukes. '• 



> VTurbellaria. Planarians. J 



CcELENTERA. 



/ 



Ctenophora, e.g. Beroe. 



Actinozoa or Anthozoa. Sea-anemones. Alcyonarians and re- 

 lated corals. 

 Scyphoniedusae or Acraspeda. Jelly-fishes. 

 Hydrozoa. Zoophytes and medusoids. 



PORIFERA. 



Sponges. Calcareous and non-calcareous. 



PROTOZOA 



Infusoria. Rhizopoda. Sporozoa. 

 Simplest forms of animal life. 



