CONTENTS. 



Page. 



Preface • 7 



Part I. — The Mesozoic Echinodermata, by William Bullock Clark 9 



Introduction ! 9 



Geologic and geographic range 9 



Bibliography 14 



Triassic Echinodermata 21 



Crinoidea 21 



Pentacrinidaa 21 



Encrinidas 22 



Stelleroidea 23 



Amphiuridfe ' 23 



Echinoidea 23 



Cidaridse 23 



Jurassic Echinodermata 25 



Crinoidea 25 



Pentacrinidte 25 



Stelleroidea 28 



Asteriidte 28 



Ophiolepididse 29 



Echinoidea 30 



Cidaridae 30 



Hemicidaridse 31 



Diadematidte 32 



Pedinidae 33 



Pygasteridrc 33 



Cassidulidse ' 34 



Cretaceous Echinodermata 35 



Crinoidea 35 



Pentacrinidte 35 



Uintacrinidre 36 



Marsupitidte 39 



Bourgueticrinidie 39 



Stelleroidea 41 



Astropectinidae 41 



Pentagonasterida? 41 



Atheneidje 42 



Pentacerotidae .' 42 



Ophiolepididae 43 



Echinoidea 44 



Cidaridae 44 



Saleniidse '. 49 



Hemicidaridae 52 



Orthopsidae 54 



Diadematidfe 55 



Diplopodiida? 58 



Cyphosomatidas 59 



Triplechinida? 63 



Pygasteridae 65 



Clypeastridao ". 67 



Echinoneidae 67 



Nucleolitidae 68 



Cassidulidae 72 



Echinocorythida; 81 



Spatangidae 86 



3 



