viii 



LIST OF ILLUSTRATIONS IN TEXT. 



FIG. PAGE 



56. Internal cast of a BracMopod shell, Camarophoria .... 110 



57. Muscle-scars in a shell of Lingiila ....... 110 



58. Types of Brachiopod Orders : Iphidea, Orhiculoidea, Clitamhonites . 112 



59. A spire-bearing Telotrematous Brachiopod : Spirifer .... 114 



60. A loop-bearing Telotrematous Brach:opod : Magellania . . . 114 



61. Structure of a Bryozoan zooid ........ 116 



62. A Trepostomatous Bryozoan : Callopora. (After Ulrich) . , . 118 



63. A Cryptostomatous Bryozoan : Fenestella. (After Ulrich) . . . 118 



64. Cyclostomatous Bryozoa : Stomatopora, Bereiiicea. (After Gregory) . 119 



65. Cheilostomatous Bryozoa : Memhranipora, Onychocella. (From Gregory) 120 



66. Shell of Chiton squaniosus ......... 124 



67. A FteroTgod, Cleodor a pyramidata ....... 125 



68. Shells of non-marine Mollusca : Unio, Corbicula, Pisidiwn, Helix, 



Paliidestrina. (From B. B. Woodward) 128 



69. Eocene Gastropods and Lamellibranchs : Cyprina, Pholadomya, Crassa- 



tellites, Cypraea, Clavalithes, Cardita ...... 130 



70. A Senonian Lamellibranch, Siwiidylus spinosus ..... 132 



71. Cretaceous Lamellibranchs : Neithea, Actinoceranius .... 132 



72. Lamellibranchs of the Lower Lias, Hippopodium, Gryphaea . . 137 



73. Plcurotomaria Quoyana and P. platyspira ...... 138 



74. Carboniferous Lamellibranchs : Carbonicola, Posidonomya . . . 139 



75. Lower Palaeozoic Lamellibranchs and Gastropods : Cardiola, Pterinaea, 



Belleroplion, Platyceras, Maclurea ....... 140 



76. Conularia quadrisidcata, Coal Measures ...... 141 



77. Miocene Pteropods : Hyalaea, Vaginella . . . . ... 144 



78. Cephalopoda : Rhyncholiths, Nautilus, Loligo ..... 145 



79. Shells of Endoceras. (After Holm and Foord) 147 



80. Primitive Nautiloidea : Piloceras, Orthoceras ..... 148 



81. Initial chambers of Cephalopod shells. (From Foord and Crick) . . 150 



82. A Nautilus and an Ammonite ........ 151 



83. Aptychus of an ammonite ......... 153 



84. Animal and shell of a Belemnite. (After D'Orbigny) . . . 154 



85. The Belemnite and its descendants : sections of shells .... 155 



86. Cephalopods with thin enclosed shell : Belemnoteuthis, Dorateuthis . 156 



87. Female Argonaut .... ..... 157 



88. Actinoceras Bigsbyi, siphuncle. (From Foord) ..... 158 



89. Three-lobed aperture of Gomphoceratid ...... 159 



90. Four-lobed aperture of Gomphoceratid ...... 159 



91. Ascoceratidae. (From Foord, after Lindstrom) ..... 160 



92. Palaeozoic Nautiloidea; Ophidioceras, Hercoceras, Apheleceras, Vesti- 



nautilus ........... 162 



93. Goniatites : Pronorites, Glyphioceras, Agathiceras. (From Foord and 



Crick) 164 



94. Ceratites nodosus . . ....... 166 



95. Ammonites: Trachyceras, Lytoceras, Coeloceras, Phylloceras . . . 168 



96. Cretaceous Ammonoidea : Crioceras, Heteroceras, Turrilites, Macro- 



scaphites, Hmnites, Scaphites, Baculites ...... 172 



