INDEX. 



Abdominalia (Cirripedia), ' 

 177; characters, 182 



Abyla, 81 



Acalephoe, 84, 87 



Acarida, 201 



Acarina, 200, 201, 202 



Acanthocephala, 141 ; charac- 

 ter of, 151 



Acanthometrina, 52 



Acanthospongia, 58 



Acephala (Mollusca), 251 



Acervulina, 49 



Acetabula, 270, 271 



Achetina, 219 



Achtheres, 178 



Acicula, 268 



Aciculidce, 265, 268 



Acineta, 64 



^cwcea, 266 



Acrotreta, 248 



Acteonia, 267 



Actinia, 100 



Actinidce, 99, 100; develop- 

 ment of, 101 



Actinomeres, 111 



Actinophrys, 45, 50, 52 



Actinosoma, 98, 99 



Actlnozoa, 97 ; general cha- 

 racters of, 97, 98 ; divisions j 

 of, 99 ; distribution of, 115 



Aculeus, 223 



Adelarthrosomata, 202 



^Eginidce, 87 



jEginopsis, 87 



^Eolidffi, 2C4, 267 



^o/t's, 267 



Agathistega, 50 



Agelacrinites, 135 



Alcyonaria, 99 ; characters 

 and divisions of, 106, 107 ; 

 distribution of, in time, 119 



Alcyonidce, 107 



Alcyoniurn, 107 



Alveolus (Belemnite), 278 



Amber, insects preserved in, 

 226 



Ambulacral system (of ZJcrAi- 

 rcu.'O, 126 



Ametabola, 214, 216 



Ammonites, 281, 282, 284 



Ammonitidce, 279; characters 

 of, 280 ; distribution of, in 

 time, 284 



Amoeba. 6, 42 ; structure of, 

 43 ; reproduction of, 44 



Amoebea, 43, 45 



Amphidlscs, 56 



Amphipoda, 177 ; characters 

 of, 190 



Amphispongia, 58 



Ampullaria, 266 



Analogy, 14 



Anarthropoda, 159 



Anatina, 257 



Anatinidce, 256. 257 



Ancyloceras, 280, 282 



Ancylus, 268, 283 



Androphores, 83 



Anguillula, 153 



Anguillulidce, 153 



Anisonema, 64 



Annelida, 159 ; characters of, 

 160; pseudo-haarnal system 

 of, 161 ; orders of, 162 ; dis- 

 tribution of, in time, 168 ; 

 phosphorescence of, 64 ; ur- 

 ticating cells of, 67 



Annulata (see Annelida) 



Annuloida, 121 ; divisions of, 

 121 



Annulosa, 159 ; primary di- 

 visions of, 159 



Anodon. 256 



Anomura, 177 ; characters of, 

 193 



Anoplura, 216 



Antenna?, of lobster, 176 ; of 

 Arachnida, 198 ; of Myria- 

 poda, 207 ; of Insecta, 213 



Antennules of lobster, 176 ; 

 of Limulus, 188 



Antipathes, 103, 119 



Antipathidce, 103, 108. 119 



Antlia, 211, 222 



Ants, 224 ; communities of, 

 224 ; slave-making instinct 

 of, 225 ; relations with 

 Plant-lice, 225 



Aphaniptera, 221 



Aphides, 218 ; alleged parthe- 

 nogenesis of, 29 



Aphrodite, 166, 169 



Apiocrinidee, 134, 139 



Aplysia, 267 



Aplysiadce, 264, 267 



Apoda (Cirripedia), . Ill ; cha- 

 racters of, 182 



Apodemata, 174 



Apolemiadce, 84 



Aporosa (Corals), 105, 119, 

 120 



Aporrhais, 266 



Appendicularia, 242, 244 



Aptera, 214, 216 



Apus, 185, 196 



Aquiferous system (see 

 Water- vascular system) 



Arachnida, 170, 171 ; charac- 

 ters of, 197-200 ; somite of, 

 198 ; organs of the mouth 

 of, 198 ; respiratory process 

 of, 200 ; distribution of, in 

 time, 205 



Araneida, 203 ; chai acters of, 

 204 ; webs of, 204 ; rt pro- 

 ductive process of, 204 ; 

 distribution of, in time, 206 



Area, 256 



Arcadte, 255, 256 

 [ Arcella, 45, 50 

 I Aicficeocidai-it, 140 



Archceocyathus, 58 



ATchiuMcK, 208 



Archiulus, 208 



Arctisca, 201 



Arenicola, 168, 169 



Argonauta, 270 ; shell of, 274, 

 275 ; reproductive process 

 of, 273 ; hectocotylus of, 274 



Argonautidce, 275, 281, 284 



Aristotle's Lantern, 127 



Arms, of Starfishes, 129 ; of 

 Ophiuroidea, 131 ; of Cri- 

 noidea, 133 ; of Comatula, 

 134; of Cystoidea, 135; of 

 Brachiopoua,'2i6 ; of Cuttle- 

 fishes, 270 ; of Nautilus, 278 



Aitemia, 185 



Arthrogastra, 203 



Arthropoda, 170 



Articulata, 170 



Ascaris, 152, 154 



Ascidiada, 243, 244 



Ascidioida (see Tunicata), 240 



Ascidians, solitary, social, 

 and compound, 243 



Ascoceras. 280 



Asiphonida (Lamellibranchi~ 

 ata), 255, 256, 283 



Aspergillum, 257 



Asplanchna, 157 



Astarte, 257 



Asleriadce. 131 



Asterinidce, 131 



Asteroidea, 122, 123 ; general 

 characters of, 129 ; families 

 of, 131 ; distribution of, in 

 space, 138 ; in time, 140 



