THE MAIN KINDS OF FOSSILS 33 



♦Class Hydrozoa: the hydroids and conularids. 



Class Stromatoporoidea: the stromatoporoids, extinct, coral-like animals. 

 ♦Class Scyphozoa: the jellyfish. 

 Class Anthozoa: the corals and sea anemones. 

 ♦Phylum Platyhelminthes: the flatworms. 

 ♦Phylum Nemathelminthes: the threadworms. 

 ♦Phylum Trochelminthes: the rotifers or wheel -animalcules. 

 Phylum Bryozoa: the moss -animals. 

 Phylum Brachiopoda: the lamp-shells or brachiopods. 



Class Inarticulata: brachiopods without "teeth" (locking devices) on the hinge of the shell. 

 Class Articulata: brachiopods with "teeth" (locking devices) on the hinge of the shell. 

 Phylum Mollusca: soft -bodied, highly organized invertebrates. 

 ♦Class Amphineura: the chitons or coat-of-mail shells. 

 Class Pelecypoda: clams, oysters, scallops, and their relatives. 

 Class Gastropoda: the snails and their relatives. 

 ♦Class Scaphopoda: the tusk-shells. 

 Class Cephalopoda: the squids, devilfish, octopus, pearly Nautilus, ammonites, and their 

 relatives. 

 Phylum Annelida: the segmented worms. 

 *Phylum Onychophora: a small group of animals with both annelid and arthropod characteristics. 

 Phylum Arthropoda: segmented animals with jointed appendages. 



Class Crustacea: the lobsters, crabs, crayfish, and their relatives. 



Subclass Ostracoda: minute bivalved crustaceans. 

 Class Arachnoidea: the scorpions, spiders, and eurypterids. 

 Class Trilobita: the trilobites, an extinct group. 

 Class Insecta: the insects. 

 Phylum Echinoderma: animals with a skeleton made up of limy plates. 

 Subphylum Pelmatozoa: stemmed echinoderms. 

 ♦Class Edrioasteroidea: seat-stars, extinct. 

 Class Cystoidea: the cystids and blastoids, an extinct group. 

 Class Crinoidea: the crinoids or sea-lilies. 

 Subphylum Eleutherozoa: stemless echinoderms. 

 Class Stelleroidea: the starfish and their relatives. 

 Class Echinoidea: the sea urchins. 

 ♦Class Holothuroidea: the sea-cucumbers. 

 Phylum Chordata: animals with a dorsal nerve cord. 

 Subphylum Hemichordata: tongue worms and their relatives. 

 Class Graptozoa: the graptolites, an extinct group. 

 Superclass Pisces: the fishes and their relatives. 

 Class Agnatha: the jawless fishes. 



Class Placodermi: primitive, extinct, plate -armored fishes with jaws. 

 Class Chondrichthyes: cartilaginous, jawed fishes; sharks, skates, rays. 

 Class Osteichthyes: bony fishes. 



Superclass Tetrapoda: chordates with a backbone and 2 pairs of limbs. 

 Class Amphibia: salamanders, frogs, and their relatives. 

 Class Reptilia: the reptiles; turtles, snakes, alligators, lizards, dinosaurs, flying reptiles, 



sea-going reptiles, and their relatives. 

 Class Aves: the birds. 

 Class Mammalia: the mammals. 



■ — ■ 



♦Groups with little or no fossil record. 



Phylum Protozoa 



The Protozoa are the simplest of animals and consist of a single cell. Most of them are 

 microscopic and leave no trace of their existence after death. Two exceptions are the orders 

 Foraminifera and Radiolaria which form part of the class Sarcodina. 



