TABLE OF CONTENTS. V 



Structure and anatomy — Continued. 

 Radials — Continued. 



Articular faces of the radi;ils — Continupd. 

 Family Antedonidje — Continued. 



Subfamily Batliymefrinre — Continued. P«g«. 



Trichometra cuhensis 65 



Nanometra bowersi 65 



Thaumatometra tenuis 66 



Family Pentametrocrinida? 6R 



Pentametrocrinus japonicus 68 



Pentametrocrinus semperi 69 



Key to recent couiatulids based upon character found in articular faces of radials 6f> 



Post-radial elements 78 



General features 78 



Post-radial homologies lO.S 



First brachial pair 103 



Homologies of the division series of two ossicles 104 



Eudiocrinus and Uintacrlnus 105 



Pentametrocrinida; and Atopocrinus 107 



Homologies of the division series of four ossicles 108 



Irregularities in the occurrence of the division series of 4(34-4) 108 



Systematic distribution of the division series of 4(3+4) 110 



Caplllaster and Nemaster 110 



Comatella, Neocomatella, and Palreocomatella 114 



Distal arm division 114 



Nomenclature of the different types of post-radial structure 116 



Adolescent autotomy and the reduplication of the arms 116 



Young of the comatulids 116 



Interpolated division series 118 



Process of arm reduplication 119 



Phylogenetic sequence of the arms on each ray 123 



Ontogeuetical, phylogenetical, and morphological sequence of the first brachial 



pairs and their reduplications !-•'' 



Brachials of the free undivided arm beyond the first pair '-6 



Brachials of the arms of the multlbrachiate species 120 



Arm tips 1^1 



Pinnules ^^- 



General features 132 



Oral or proximal pinnules 140 



Middle or genital pinnules , 149 



Distal pinnules 154 



Pinnules and cirri 15S 



Types of intersegmental union 159 



Genera] features 159 



Union of radials with each other and with centrodorsiil, and union of calyx plates- 160 



Nonmuscular unions 162 



General remarks 162 



Syzygy 16o 



Paeudosyzygy 174 



Synarthry 176 



Cryptosynarthry 177 



